My father always said: "Ask ten developers to estimate how long it will take and then add their answers together :-)" On a more serious note I think you need to look at other factors 1) Risk a) Have I done this before? b) How well is the problem/solution specified - are all the factors understood? c) Is this novel in any way? New platform, new software, new interfaces 2) Have I allowed enough time for other things? a) Meetings/discussions b) Weekely progress reports - (even if you only write them to yourself they focus the mind on what you really got done!) c) Keeping the documenation up to date and manageing changes This is a BIG time sink!!!! d) email, admin and all the other things that only make you productive 40-60% of the time 3) Complexity. How many data connections and control flows are there netween my modules and between my system and other systems 4) How many thinks can go wrong 5) How many people are involved Alec alec.clews@merant.com