I have enough spare parts to be able to change out any part that does not requir fitting, is dissassembled during field stripping, or can be replaced without any sort of significant adjustment being made.
Guide rod
Recoil spring
Recoil spring cap
Firing pin
Firing pin spring
Firing pin stop
slide stop
grips
grip screws
grip bushings
extractor
I don't have one, but a barrel bushing is a good idea as well.
These are all parts that can be put on by me, at the range, don't require a smith or special tools.