Since I rarely begin new projects and have several loyal clients, overhead such as bookkeeping, estimates and talks is relatively small. (Especially estimates:

Since I rarely begin new projects and have several loyal clients, overhead such as bookkeeping, estimates and talks is relatively small. (Especially estimates: usually I don't estimate at all, just get the work done and bill for it later; and most talks and customer travel, when still unavoidable, are done by my partner who is non-programmer). This works other way too: I usually avoid new clients to minimize overhead. Also the overhead is exactly the reason I don't hire people: time and energy to spend on management are tremendous and up to this moment I wasn't been able both to hire someone and make profit from it. So, my model doesn't work well for teams. Or maybe I suck at management. Another problem is time spent idling: my time in the office varies from 5 to 8 hours, when I switch from tasks I'm often distracted by non-work things such as reading news, lunch, occasional gaming. The main non-obvious downside with pay-by-hour model is that when I try to be more effective, I spend more energy, but get less money. P.S. Can't provide exact numbers now because not in the office.