Hour building in Florida right after PPL & IMC, I borrowed one of the FTO's Cessna 152s (an airframe which I hadn't used before) and assumed that it was fitted with long-range tanks (36 US gallons if I recall). I then set out on a longish VFR nav - with a divert en route due weather - and on landing back at "home base", was shocked to discover that the plane was fitted with... standard tanks (24 US gallons)!
A quick calculation showed I had actually used 95% of the on-board fuel... Not much to play with in case of a go-around!
Lesson learned: never assume, always double-check!
Cheers
