The 150 is much more prone to carb icing. It's to do with the engine configuration (is that the right word?), and I've been shown why, and instantly forgotten. But from the point of view of the pilot, in the 150 you probably need to apply carb heat about every five minutes, put it on if you have to hold before takeoff, and be constantly alert for any changes in RPM which could possibly mean carb ice. Yes, I know you do that in the 152 as well, but it's much more important in the 150.