There's very few build that I keep track of time on....because time spent on a model is time that does NOT count against you (unless you keep track of your time!) It is a huge variable, depending on how much you want to put into it. I've knocked out a Tamiya P-51 in as little as 15-20 hours...that said, I've also put in 50-60 hours on another example of the same kit....adding all sorts of good stuff.
Last year, after the work season started up, I hadn't built anything in over a month...we got a rain day, so I parked myself at my bench and hammered out this F-18D from start to finish, in a one day "power build"! Actual time spent building...12 hrs or so.
In contrast, I spent close to 200 hours on this 1/48 Barracuda. Scratched(mostly) interior, landing gears, wing fold...rescribed and riveted(one by one w/ a needle)