If you saw their fleet maintenance shop, you’d question if they dispose of anything lol. They need dozens of spares and anything that they can’t fix mechanically, they use for parts (ie cab and compartment doors)
The only thing that surprises me is how the paint isn’t more destroyed on the old spares due to the constant use of duct tape for numbering lol
They don’t always replace tower ladders with a spare of the same length. Many times you’ll see a company that normally runs a 95 ft with a 75 ft spare, so dispatch tries to confirm which rig co.s are in when the BC or Division requests a certain size tower as a special call truck for a Box.
For straight stick ladders, it doesn’t matter, though, b/c they’re all 100 ft rear mounts