I've also been told that most people take 2-3 hours to be checked out on a C152 - having previously only flown PA28 & 38.
Why? Took me 40 minutes worth of ccts and GH. The thing is virtually uncrashable anyway, I reckon you would have to be pretty determined to balls up in a 152. Although before the links to 7 squillion accident reports for 152's get posted I do know that people achieve the near impossible and total them.