I spend approximately 5 minutes per month on payroll - Gusto user (former Microsoft officemate/friend is eng hire #2 there). There may be better tools than Gusto, but it's good enough that I don't think about it.

Another point: running any kind of client service business, to a first approximation, is 100% about getting the right kind of clients. I spent a while a few years ago doing "contracting" for bottom-of-the-barrel Craigslist wannabes and other jokers and it was horrible. Going from being a pure dev employee to contracting because you 'hate office politics' is a route to failure; it requires a lot more planning, especially over cashflow, and client relationships.