Forum Moderators: mack
For bespoke stuff it's down to what support level you are providing and what is defined as a 'bug' versus 'feature'. The 15-20% rule for packaged stuff just does not fit a bespoke environment as you have one user who has to pay to cover all future support time. Try a monthly retainer or a bank of hours system. Either way don't be afraid to ask for a fair amount whatever that turns out to be.