^^Solid advice. The only thing I might add is to record these hours somewhere and then in your future quotes include a portion of time called maintenance, bug f

^^Solid advice. The only thing I might add is to record these hours somewhere and then in your future quotes include a portion of time called maintenance, bug fixes, testing or something similar that accounts for these unforeseeable problems. Some clients will use more than the allotted time, some less. Over time it will average out. You may have to explain to them why code \might\ need bug fixes etc but that generally leads to the client having a better overall understanding of the work required which never hurts :)