I've gone down 5-6 stairs before. . . It was alright and my wheel is still pretty true
I've gone off a 3 stair like it was a ledge but I think that's about the biggest i'd ever do. (it's those really hard landings that will bend a rim.
Never up
I can wheelie when I have my riser bars on my bike (almost never) about 3-4 cranks. . . I ride a 44x16 with 700 rear wheel and 165 cranks if anyone wants to do the math.