The longest it has taken me- well Im currently working on 2 dios that should not be done for awhile. The longest so far was probably a month with the figs and base.
The shortest was a dio I did was in 2 days, figs and a base.
The longest for just a build, Tamiya tiger late, running on 7 months now.
the shortest time for just a build, couple hours for 1/72 jeep.