Bit of an odd question?
I say just get on with it.
If you're going to be very tidy with cable management then it'll take a bit longer than if you just stuck everything in.
Don't rush, take time and make sure your grounded.
I've just built a system in a Fractal R2. Started the build at 1PM, finished about 4.35.
Took an hour bench testing the parts before going in case, and working out the best way to do cable management.
Very happy with the results, despite the few reviews about cooling, I'm actually getting the same / slightly better temps than I had in my old Silverstone case.
cool, have you built rigs before? or was this 3:35hrs for a nooby