My empirically-confirmed heuristic is that the time to deliver a feature set that someone would actually want to use is 2.5x-3x of the time I think of when aske

My empirically-confirmed heuristic is that the time to deliver a feature set that someone would actually want to use is 2.5x-3x of the time I think of when asked for an off-the-cuff estimate. Basically, multiply initial estimate by a number between e and pi -- no joke! It's a bit of a problem given that PM's think they're being generous with a 20% pad.