Don't hire for pleasure; hire to kill pain. Always ask yourself: What if we don't
hire anyone? Is that extra work that's burdening us really necessary? Can we
solve the problem with a slice of software or a change of practice instead? What
if we just don't do it?
Similarly, if you lose someone, don't replace him immediately. See how long
you can get by without that person and that position. You'll often discover you
don't need as many people as you think.
The right time to hire is when there's more work than you can handle for a
sustained period of time. There should be things you can't do anymore. You
should notice the quality level slipping. That's when you're hurting. And that's
when it's time to hire, not earlier.