Many freelancers will back me up when I say that when you work for yourself, it's hard not to say yes when a job opportunity comes your way. You never know when the next payment is coming, and some opportunities are too good to pass up. But remember to value your time and skills: there is no shame in saying no, especially if the pay isn't right, the job doesn't excite you, or you already have too much on your plate. Even if it's for a friend.