Do you have a rule or standard for rewind vs replacement of electric motors

we usually do rewinding if the winding resistance and winding insulation resistance fail, instead of re-baking/ re-varnishing... while we do replacement if the mechanical aspects of electric motor fail like shafting (bent, corroded, etc.), end-covers (excessive rust build-ups, etc.), casing (rust build-ups, damaged), bearing seats (loose bearing hold, cannot be machined, etc.), stator core (rust build-up, exposed to weather)...

Replacing with energy efficient motors may be economical than rewinding large motors due to increased losses as a result of burnout.

Time is also a factor. Rewinding can be done in 6 weeks where the lead time on a new motorcan be 6 months. I've strapped the pieces to a pallot before and had the rebuilt motor back in 4 weeks.