Ask most business owners who their best client is and they’ll name the one who pays the most. It’s a natural answer. Big invoices feel like security. But revenue is only half of the picture. A client who pays $10,000 a year and takes 300 hours of work is earning you about $33 an hour. A client who pays $4,000 and takes 40 hours is earning you $100 an hour.

When a business is stuck or struggling, this difference matters a lot. Many owners find that a few clients bring in most of the profit, while others, including some of the largest, quietly cost more in time and stress than they pay. Without measuring it, you can’t see which is which.

The exercise takes an afternoon.

List every client from the last twelve months. Next to each one, write how much they paid you in total.

Estimate the hours each one took. Include everything: the work itself, calls, emails, revisions, chasing payments. If you don’t track time, make an honest estimate. A rough number is far better than none.

Divide pay by hours. That’s your real hourly rate for each client. Sort the list from highest to lowest.

Add one more column: stress. Mark each client easy, average or difficult. Some clients pay well but drain you. That’s a cost too.

The list usually tells a clear story. At the top are a handful of clients who pay well for the time, treat you well and are often similar to each other in some way: the same industry, the same size, the same kind of project. At the bottom are clients earning you far less than you thought, often with the most revisions and the most late payments.

That story points to your next move. Find more clients like the ones at the top. Raise prices or change terms for the ones near the bottom. And consider letting go of one or two of the worst, which frees up time for work that actually pays.

I’ve really appreciated working together. As I look at my schedule for next year, I’m narrowing my focus, so I won’t be able to take on new projects for you after March. I’m happy to recommend someone who’d be a good fit.

Run the same exercise once a year. Client lists drift, and a client who was a great fit three years ago may not be one now.