Rebuilding a friend's MTB/sorta cross-bike for him, I could not get the drive side crank arm off. Threads stripped the first time I tried. The BB was a Shimano cartridge cheapie (OEM) that used a plastic cup on the driveside
, so I couldn't effectively pry it, even with some large washers that I cut out to fit over the spindle put it. I also tried chuck wedges to no avail.
Since the BB felt OK, I just left it. If the BB goes bad, I guess it is cutting time. I have a pair of newer crank arms for it.