I work as a sound mixer for film and estimating how long it will take is always hard, but I never really got a bad reception when I just said: I canlt tell you unless I see the thing.
Hell if you ask a mechanic to fix your car they will also have to check the thing first before deciding how long it is going to take.
This is the professional thing to do: gauge the situation, take tour time to figure out the scale of the thing as long as you need and then give a pessimistic guess with a disclaimer that things can easily get out of hand without anybodies fault if unforseen problems arise.
Right, but there's a big difference between "Don't estimate until you've done your due diligence" and "Don't estimate".
It's perfectly reasonable to say "This is a big project, it'll take me a week to know where we stand"- there, you've provided an estimate of the scoping task and promised an estimate in the future as well.
Hell if you ask a mechanic to fix your car they will also have to check the thing first before deciding how long it is going to take.
This is the professional thing to do: gauge the situation, take tour time to figure out the scale of the thing as long as you need and then give a pessimistic guess with a disclaimer that things can easily get out of hand without anybodies fault if unforseen problems arise.