Writing software on a consulting basis can often be a losing proposition for developers or clients or both. There are too many things that can go wrong, and that ultimately translates into loss of time and money. The “15% rule” we’ve come up with is intended to create a win-win situation for both parties (or at least make it fair for everyone). Clients generally get what they want, and development shops make a fair profit. It’s not a perfect solution, but so far it seems to be ...