The more, the merrier — until you’ve had enough.
For example, you might think that you can never have enough clients. More clients mean growth; more profit, more employees (if you own a company)... and more work. If you’re doing everything right year after year, this is the scenario you can certainly expect.
However, with everything mentioned comes more pressure and more deadlines to meet, and almost not enough time. If you constantly find yourself completely burnt out at the end of the workweek, or notice that each weekend passes with you still tinkering with your tasks — it’s time for a change.