Some of the items that have needed replacement or repair:
- Timing belts - these just break! It is worth buying a few extras, particularly for the spindle.
- Spindle motor - this blew out after a few years and I bought a replacement. If it happens again, I will ditch it and go to a servo motor.
- Spindle index - this stopped working so I changed it for a 3D printer optical endstop which works quite well.
- Stepper motor - I had one on the X axis that I think had a bearing problem, but it was easy to replace.