Hardly ever use it, won't leave without it. Kinda like my winch.
I can think of a few situations:
Frame deep in mud, stalled my 8274. Hi-lift it up and pull forward, repeat, until out.
Frame broke on someone else's Heep, pulled ends together close enough to patch it together (remember you can pull and push with these)
Hi-centered, then not thanks to hi-lift
Trailer jack sank in ground, couldn't hitch it up as tongue was below ball. jacked up (large) trailer with rig on it and got it hitched up.
Couldn't get my bumper mounted as frame ends were a little tweaked. Pulled together with Hi-lift. Not a trail fix, but it sure worked good.
These were all over a long period of time, but when you need one you need one. The only thing I really DONT like them for is changing tires, unless you chain the frame to the axle. Given the flex and height we have today you really have to max it out to get a tire off the ground otherwise.
The down side is, they can kill you. If that handle comes up wrong look out. Also, at max lift you are usually wishing you had a better jacking point on the vehicle so it doesn't slip off.
Anyway, I like them.