How to Choose an ERP System for Your Growing Business

A practical guide to evaluating ERP software for businesses of any size. What to look for, what to avoid, and how to run a proper selection process.

Why ERP selection matters more than you think

Most businesses don't buy ERP software once. They buy the wrong software, suffer through it for two or three years, then go through a painful migration to the right system. The average cost of a failed ERP implementation — in lost productivity, data migration, and staff time — is significant for any business.

Getting the selection right the first time saves money, saves time, and saves your operations team a lot of headaches.

The four criteria that actually matter

1. Does it handle your local compliance?

This is the most important question, and the one most businesses ask last. Your ERP needs to handle:

• Tax calculation and filing (VAT, GST, sales tax, or whatever applies in your jurisdiction)
• Payroll and statutory deductions (income tax, social security, pension)
• Reporting formats your regulators require

If your ERP can't handle these natively, you'll end up with a patchwork of add-ons, workarounds, and manual processes. Ask vendors specifically: "How does your system handle [your country's] tax rules?" If the answer involves a third-party integration or a manual export, that's a red flag.

2. Is it truly integrated — or just "connected"?

Many vendors claim their system is "all-in-one" when in fact it's several separate products connected by an integration layer. The difference matters:

Truly integrated: One database. When you make a sale, your stock, your accounts, and your CRM all update simultaneously. No syncing, no API calls, no lag.

Connected systems: Separate databases that exchange data on a schedule. Your stock system sends data to your accounting system every hour. Your accounting system sends data to your reporting tool every night. Errors accumulate at every junction.

Ask vendors: "Is this one database or multiple systems connected by an API?" The answer tells you everything.

3. Is the pricing transparent?

ERP pricing is notoriously opaque. Common tricks to watch for:

• Per-module pricing that adds up to 3x the advertised price
• Per-user pricing with no cap
• "Implementation fees" that dwarf the licence cost
• Annual price increases not disclosed upfront

Ask for total cost of ownership over 3 years, including all modules you need, all users you expect to have, and any implementation or training costs.

4. Can you actually get support?

ERP problems happen at the worst possible times — end-of-month close, peak trading, payroll day. When something goes wrong, you need someone who picks up the phone.

Ask: "What is your SLA for critical issues? Can I speak to a human?" Check reviews on independent platforms. Look for comments about support response times, not just product features.

The red flags to watch for

• Demo environment only — if the vendor won't let you trial the actual product, ask why
• "Custom development required" — for standard features, this means the product doesn't do it natively
• Long implementation timelines — a 6-month implementation for a 20-person business is a sign of complexity, not capability
• No local case studies — if the vendor can't show you a customer in your industry and your country, they may not understand your compliance requirements

A practical evaluation process

Step 1 (Week 1): Define your requirements. List every process you need the system to handle. Group them into must-have, should-have, and nice-to-have.

Step 2 (Week 2): Shortlist 3 vendors. Score each against your requirements list. Eliminate any that can't handle your compliance needs natively.

Step 3 (Week 3): Run demos. Give each vendor the same scenario: walk me through a full sales cycle, a payroll run, and a tax return for [your country].

Step 4 (Week 4): Trial the winner. Insist on a free trial with your own data, not a pre-loaded demo environment.

Step 5: Check references. Ask for three customers in your industry. Call them.

Why businesses choose OpesFlux

OpesFlux puts the till, stock, purchasing, invoicing, accounts and payroll in one database, with published prices from £19 a month. It's honest about its gaps too: it doesn't submit VAT returns or RTI to HMRC, and it doesn't track batches. Each industry page and comparison says where it fits and where it doesn't.

OpesFlux is new, so it can't yet give you three reference customers in your trade. What we can do is run a demo with a scenario from your own business, including a sales cycle and a payroll run.

Working out your stock levels? Our free reorder point calculator shows when to reorder and how much safety stock to hold.