>>vimes6+(OP)
Work expands to fill the time you have. If you don't set a goal, you'll never ship. Estimation is not an exact science, but, I rather set a goal post that I can move if I need to than not have one at all.
>>webarc+W5
The problem is that negotiations phase where the devs get screwed down on the “price”. This is of course a silly thing for management to do given they are paying by the hour anyway!