It's tempting to assume that your biggest customer is also your best customer, but revenue alone rarely tells the whole story.

Consider two hypothetical consulting clients.

Customer A pays £5,000 for a project but requires numerous meetings, additional revisions and constant support. Customer B pays £3,000 for a clearly defined project, makes decisions promptly and is delighted with the results.

Without examining the costs and effort involved, we can't say which customer is more profitable. But Customer B could easily deliver a better return, particularly if they also become a source of repeat business and referrals.

The point is that customer value has several dimensions.

For this audit, we're going to examine five:

1. Financial contribution: How worthwhile is the business financially, after direct costs?

2. Delivery efficiency: How much time, effort and additional work does serving this customer require?

3. Problem–offer fit: How well does your product or service solve the customer's problem?

4. Working relationship: How easy and productive is the relationship?

5. Future value: Is there realistic potential for repeat business, additional sales or referrals?

Together, these five factors provide a more balanced view of customer value than revenue alone.

Now it's time to put the principle into practice.

Start by identifying your five most recent customers. Ideally, choose customers whose work you've completed, or delivered enough of to make a reasonable assessment.

If you have fewer than five, use the most relevant recent examples available. The important thing is to start with real evidence rather than assumptions about your ideal customer.

Step 1 — Gather the facts

Download the free Right Customer Audit Worksheet and complete the first table.

For each customer, record:

- The customer or customer type, and what they purchased.

- Revenue generated and approximate direct costs.

- The time involved and any significant delivery challenges.

- Evidence of repeat business, referrals or future opportunities.

For this exercise, treat financial contribution as revenue less directly attributable costs, and assess your own delivery time and effort separately. This gives you a useful comparison without treating a simple revenue figure as profit or counting the same effort twice.

Don't get stuck looking for perfect information. Reasonable estimates are useful, provided you're clear about what you know and what you're assuming.

Step 2 — Score each customer

Using the worksheet, rate each customer against the five customer-value criteria.

Use a simple scoring scale:

Score         Meaning

1 — Poor - Low value, significant problems or limited potential

2 — Acceptable - Mixed results, reasonable value but room for improvement

3 — Strong - Good commercial value, positive experience or strong potential

Apply the ratings consistently across all five customers. Use actual figures where possible, particularly for financial contribution, and avoid giving a high score for future value unless there's a credible reason to expect it.

Each customer receives a total score out of 15.

Step 3 — Interpret your scores

Total score  What it suggests

12–15             Strong customer — look for opportunities to attract more like them

9–11                Worth reviewing — identify what could improve the commercial relationship

5–8                  Question the value — reconsider pursuing similar work on the same terms

These scores are a guide, not an absolute rule. A customer who repeatedly pays late or creates serious delivery problems may be a poor fit despite a relatively high score.

Likewise, a customer who scores lower today might represent a worthwhile strategic opportunity if there's credible evidence of future value.

Five customers won't prove an 80/20 relationship or establish your ideal market with certainty. The purpose is to reveal useful patterns that you can investigate and test.

Once you've completed the scorecard, don't just look at which customer has the highest score.

Look for the characteristics your strongest customers have in common.

What do your best customers have in common?

Are they in a particular industry? Do they have similar problems, budgets, business sizes or attitudes towards investing in solutions?

Why are they good customers?

Is it because they value your expertise, make decisions quickly, have clear requirements or appreciate the results you deliver?

What warning signs appear among your least attractive customers?

Do they focus heavily on price, expect extensive additional work, struggle to make decisions or need services outside your core expertise?

What would you change if you could start those relationships again?

Sometimes the problem isn't the customer themselves. It may be unclear expectations, poor qualification, weak pricing or a service that needs a better delivery process.

That's an important distinction because it influences whether you should change the customers you target or improve how you serve them.

Record your findings in the second page of the worksheet.

You now have the evidence to create a clearer picture of the customers you should be actively pursuing.

We're not trying to build a detailed marketing persona containing dozens of demographic characteristics. We want a practical description that helps you recognise a promising prospect and make better decisions about where to invest your time.

Complete this statement:

Our best customers are [type of customer], who struggle with [important problem], value [the result we deliver] and are commercially attractive because [the characteristics that make the relationship worthwhile].

For example:

"Our best customers are owners of established service businesses who need help generating consistent enquiries, value practical implementation support and are willing to invest in a structured approach to growing their business."

Your statement should be specific enough to guide your marketing, prospecting and sales conversations.

Now answer one final question:

If you could attract ten more customers like one of those you've just reviewed, which customer would you choose — and why?

Your answer should help clarify where your best opportunities lie.