I've worked with a few part's changer's before.

I've seen a new £700 traction motor fitted instead of replacing the worn top bearing on the old motor.

New complete platform safety switch assembles fitted at £60 a time because people are to lazy to fit a easily replaceable broken spring or micro switch that costs a couple of £'s.

New £1500 gearbox fitted for a leaky hub seal that's less then £10.

I've seen a llop have new traction motor, both control cards, contactors, throttle pot & switches fitted all for a blown 10 amp fuse.

It annoys me when parts get replaced / money gets wasted because people haven't a clue, they always seem to get found out for being useless in the end sooner or later.