Business Systems: Getting CRM, ERP, and MRP Right

Business systems have a reputation for being expensive, complex, and the domain of large enterprises. The acronyms alone — CRM, ERP, MRP — suggest something technical and intimidating. Many small and medium businesses either avoid them entirely or implement them badly, ending up with expensive software that no one uses properly.

This is a missed opportunity. The right systems, implemented well, transform how a business operates. They reduce manual work, prevent things falling through cracks, and let you scale without proportionally scaling your admin burden. The wrong systems, or systems implemented poorly, become expensive shelfware that creates more problems than it solves.

This guide explains what these systems actually do, when you genuinely need them, and how to approach selection and implementation without the horror stories.

What These Systems Actually Are

Let us start with clear definitions, because the terminology is often used loosely.

CRM: Customer Relationship Management

A CRM manages your interactions with prospects and customers. At its simplest, it is a database of contacts and companies with a record of your communications and dealings with them.

But modern CRMs do much more than store contact details. They track deals through your sales pipeline, automate follow-up sequences, integrate with your website to capture leads, connect with your email and calendar, and provide visibility into your sales activity.

For many service businesses, CRM is the most important system to get right. It is the hub where marketing, sales, and customer management connect. A well-configured CRM means leads do not get forgotten, follow-ups happen automatically, and you have visibility into what is happening across your pipeline.

ERP: Enterprise Resource Planning

ERP systems manage core business operations: finance, inventory, purchasing, order management, and often HR. They provide a single source of truth for operational data across the business.

The "enterprise" in ERP is somewhat misleading. While large enterprises use complex ERP systems, there are options suited to smaller businesses. The principle is the same: integrating operational functions into one system rather than managing them separately.

For manufacturing and product-based businesses, ERP typically handles order processing, inventory management, purchasing, and financial accounting. For service businesses, ERP functionality might be lighter, focusing on job costing, resource scheduling, and financial management.

MRP: Material Requirements Planning

MRP is a subset of ERP focused specifically on manufacturing planning. It calculates what materials are needed, in what quantities, and when, based on production schedules and bills of materials.

If you manufacture products with multiple components, MRP helps ensure you have the right materials available when needed without holding excessive stock. It is less relevant for pure service businesses but critical for manufacturing.

CRM: The System That Ties Everything Together

For most service businesses, CRM deserves the most attention. It is where your marketing efforts, sales activities, and customer relationships converge.

More than a contact database

If you think of CRM as just storing contact details, you are missing the point. A spreadsheet can store contacts. A CRM manages the entire relationship lifecycle.

When someone fills in a form on your website, where does that lead go? How do you ensure follow-up happens? What if you are busy with a job when the enquiry arrives? How do you remember to check back with a prospect who said "call me in three months"?

A properly configured CRM answers all of these questions automatically. The lead arrives, is assigned, triggers a follow-up sequence, and creates tasks for human follow-up at the right moments. Nothing falls through the cracks because the system handles it.

The integration hub

Your website captures leads. Your advertising generates traffic. Your content marketing builds awareness. Your email communicates with prospects. Your calendar manages appointments. These are not separate activities; they are parts of one system.

CRM is the hub that connects them. When a lead comes from Google Ads, the CRM knows. When they download a guide from your website, the CRM records it. When you send emails, the CRM tracks opens and clicks. When you book a call, it syncs with your calendar.

This integration matters because it gives you a complete picture. You can see that a prospect first found you through a blog post, later clicked a Google ad, downloaded your pricing guide, received three nurture emails, and then booked a consultation. That context changes how you approach the conversation.

Automation that works in the background

This is where CRM becomes transformative for business owners who cannot dedicate full-time attention to sales.

Consider what happens without automation: a lead comes in, you are on a job, you forget to respond for two days, the lead has moved on. Or: you have a great initial conversation, promise to follow up, get busy, and the opportunity goes cold.

With proper automation: a lead comes in, they immediately receive an acknowledgement email, a task is created for you to call within four hours, and if you do not mark it complete, you get reminded. After your initial conversation, an automated sequence sends relevant information over the following weeks, keeping you present without requiring your daily attention.

The system works in the background. You can focus on delivery, knowing that your pipeline is being worked systematically.

Email automation and nurturing

For B2B businesses with longer sales cycles, email automation is not optional — it is essential.

A prospect researching options in January may not be ready to buy until June. Are you going to manually email them every few weeks for six months? Realistically, no. But an automated nurture sequence will.

Good nurture sequences provide value, not just "checking in" emails. Educational content, case studies, answers to common questions, industry insights. Each email gives the prospect a reason to stay engaged while gently reinforcing your expertise and keeping you top of mind.

When they are finally ready to act, you are the business they have been hearing from consistently. You are familiar. You have demonstrated expertise. The sale becomes easier because the relationship already exists.

We cover email nurturing in depth in our article on Lead Magnets: Turning Content Into Pipeline.

When You Need Each System

Not every business needs every system. Here is a framework for thinking about what you actually need.

CRM: Almost everyone

If you have more than a handful of customers and any kind of sales process, you benefit from CRM. Even sole traders with simple businesses benefit from systematic contact management.

The question is not whether you need CRM, but how sophisticated it needs to be. A freelancer might use a simple tool or even a well-structured Notion database. A business with multiple salespeople and complex deals needs more robust pipeline management.

Signs you have outgrown your current approach: leads getting forgotten, inconsistent follow-up, no visibility into your pipeline, relying on memory or scattered notes, team members duplicating effort or dropping handoffs.

ERP: When operations get complex

ERP becomes relevant when your operational complexity outgrows spreadsheets and disconnected tools.

Signs you need ERP: financial data scattered across multiple systems, inventory management by spreadsheet causing stockouts or overstocking, no clear job costing, purchasing disconnected from inventory, manual processes consuming significant time.

For many service businesses, full ERP is overkill. You might need good accounting software (Xero, QuickBooks) and job management software (Tradify, ServiceM8) rather than an integrated ERP. These lighter tools cover the functions you actually need without enterprise complexity.

Manufacturing businesses typically need ERP earlier because their operational complexity is inherent to the business model.

MRP: Manufacturing with component complexity

MRP is specifically for manufacturing businesses that build products from multiple components with meaningful lead times.

If you buy raw materials, manufacture products, and need to plan material requirements based on orders and forecasts, MRP helps you do this systematically rather than reactively.

Simple manufacturing with few components might manage with spreadsheets. Complex manufacturing with many components, varying lead times, and significant inventory investment benefits from proper MRP.

The Build vs Buy Decision

Some businesses consider building custom systems rather than buying off-the-shelf software. This decision deserves careful thought.

When buying makes sense

For standard business processes, buying almost always makes sense. CRM functionality, accounting, inventory management — these are solved problems. Commercial software handles them well, updates continuously, and costs far less than custom development.

If your processes fit within what commercial software offers, even with some compromise, buying is usually the right choice.

When custom makes sense

Custom development makes sense when your processes are genuinely unique and core to your competitive advantage, commercial software cannot accommodate your requirements even with configuration, or integration between systems is complex enough that custom middleware is needed anyway.

These situations are rarer than people think. Often, "we need custom" really means "we have not adapted our processes to fit available software" or "we have not found the right software yet".

Custom systems also carry hidden costs: ongoing development for changes and improvements, dependency on developers for maintenance, no benefit from vendor improvements, and the risk of the developer becoming unavailable.

The middle ground

Many businesses find the middle ground: commercial software for core functions, with custom development for specific integrations or unique requirements. This combines the reliability and ongoing development of commercial software with the flexibility of custom work where truly needed.

Choosing the Right CRM

CRM selection is where many businesses go wrong, either choosing something too basic, too complex, or too expensive.

What features actually matter

For service businesses, these capabilities matter most:

Pipeline management — visualising deals through stages, tracking progress, forecasting revenue.

Contact and company management — storing information about people and organisations, with relationship mapping.

Email integration — sending and tracking emails within the CRM, seeing communication history.

Automation — creating follow-up sequences, assigning tasks automatically, triggering actions based on events.

Website integration — capturing leads from forms, tracking website activity.

Reporting — understanding pipeline health, conversion rates, activity levels.

Mobile access — managing contacts and deals when away from your desk.

The affordability spectrum

CRM pricing varies enormously, and expensive does not mean better for your needs.

At the free or very cheap end: HubSpot Free CRM, Zoho CRM free tier, Notion configured as a CRM. These work for simple requirements and very small teams.

In the affordable mid-market: Pipedrive (from around £15/user/month), Zoho CRM paid tiers, HubSpot Starter, monday.com CRM. These offer solid functionality for most SMBs at reasonable cost.

At the enterprise end: Salesforce, Microsoft Dynamics, HubSpot Enterprise. These cost significantly more, often £100+ per user per month, and offer capabilities most SMBs will never use.

Salesforce in particular has become synonymous with CRM but is dramatically overspecified for most small and medium businesses. It is powerful, but that power comes with complexity and cost. For every business that genuinely needs Salesforce, there are dozens using it who would be better served by something simpler and cheaper.

We cover CRM selection in detail in our article on CRM Selection for Service Businesses.

ERP Implementation: Why Projects Fail

ERP implementations have a notorious failure rate. Understanding why helps you avoid the same mistakes.

Common failure patterns

Scope creep — starting with core requirements then continuously adding "while we're at it" features until the project becomes unmanageable.

Insufficient planning — jumping into implementation without fully understanding current processes and requirements.

Poor data quality — migrating messy data into a new system just creates a new system full of messy data.

Inadequate training — expecting people to use new systems without proper training and support.

Lack of executive commitment — projects that lack sustained leadership attention drift and fail.

Wrong system selection — choosing based on impressive demos rather than fit for actual requirements.

How to avoid failure

Start with process mapping — document what you actually do before evaluating systems. Understand your requirements before looking at solutions.

Implement in phases — do not try to transform everything at once. Start with core functions, get them working, then expand.

Clean data before migration — invest time in data cleanup. Migrating rubbish guarantees a system full of rubbish.

Budget for training — plan and fund proper training. Untrained users will not adopt the system.

Secure ongoing commitment — implementation is not a project with an end date. Systems need ongoing attention.

Right-size your selection — choose a system appropriate to your scale. Enterprise systems for SMBs create unnecessary complexity and cost.

We cover implementation in detail in our article on ERP Implementation Without the Horror Stories.

Integration: Thinking Ahead

Whatever systems you choose, think about how they connect. Isolated systems create data silos, manual work, and incomplete pictures.

Common integration points

CRM to website — leads captured on your website should flow automatically into your CRM.

CRM to email — email communication should sync with contact records.

CRM to accounting — won deals should flow through to invoicing without re-entering data.

ERP components — inventory, purchasing, and finance should share data rather than requiring manual transfer.

Integration approaches

Native integrations — many systems connect directly to each other. Check what integrations exist before selecting systems.

Integration platforms — tools like Zapier, Make, or n8n connect systems that do not have native integrations.

Custom integration — for complex requirements, custom development may be needed.

Manual processes — sometimes the volume does not justify automation. A manual process done once per week might be acceptable.

We cover integration in depth in our article on Integrating Your Systems.

Cost Expectations

System costs include software subscriptions, implementation effort, training, and ongoing maintenance.

Software costs

CRM: Free to £150+/user/month depending on tier and vendor. Most SMBs should budget £15-50/user/month for capable CRM.

ERP: £50-500+/user/month depending on scope. SMB-focused options like Odoo, Zoho One, or industry-specific tools often cost £50-150/user/month.

MRP: Often included in ERP, or standalone from £100-500/month.

Implementation costs

Do not underestimate implementation. A £30/month CRM subscription might need £2,000-5,000 of setup and configuration to work properly. An ERP implementation might cost 3-5x the first year's subscription in implementation services.

Budget for this. Attempting to implement complex systems without proper support usually results in systems that do not work properly.

Ongoing costs

Training for new staff, configuration changes as your business evolves, integration maintenance, and subscription renewals. Budget 15-25% of implementation cost annually for ongoing maintenance and improvement.

Getting Started

If you are new to business systems, here is a sensible approach.

Start with CRM. For most service businesses, CRM delivers the most immediate value. Get this right first.

Choose appropriately. Do not overbuy. A simple CRM properly implemented beats a complex CRM poorly implemented.

Invest in setup. Budget for proper configuration. A system configured to your actual processes will be adopted. A generic setup will be abandoned.

Connect to your website. Ensure leads flow automatically from website to CRM. This single integration is often the highest-value connection.

Build automation gradually. Start with basic follow-up automation. Add complexity as you understand what works.

Plan for training. Everyone who uses the system needs proper training. Budget time and money for this.

Review and refine. Systems need ongoing attention. Review regularly and improve based on what you learn.

The right business systems remove friction, provide visibility, and let you focus on value-adding work rather than administrative overhead. They take investment to implement properly, but that investment pays returns for years. The key is choosing appropriately for your actual needs and implementing thoroughly rather than partially.