For the most part, things like VPIP I only need about 20 hands to get at least an idea of if someone is a fish or a nit(even a nit can get dealt premiums 10 times in 20 hands, but highly unlikely). PFR is pretty low as well. It's things like 3B and your CB stats that will take more and more hands.
The looser the player, the sooner you might get a read on those stats though. If in the first 40 hands, he has a PFR of 25% and his CB stat is 100%, he is most likely going to CB as you are working with a sample size of 10 hands previously to get the stat. Whereas if a player has a PFR of only 5% over 40 hands has a CB of 100%, you don't know as much because you've only got a sample of 2 hands.
Now with that example, you could take it how you want it, that looser villain would most likely be playing more crap than the tighter one.