It comes down to its core state "Whats it worth?"
And is there time and k/s.
Some times rebuilding a electric motor that costs 140 usd is rite and others wrong.
No single answer is correct all the time.
I look to rebuild / repair nearly everything even electronics items.
Before or after machine /system is returned to production depends upon situation.
This means, I might buy a new replacment item, then place the reworked one on shelf.
I have spares of different RFI status; red card = temporary use thoubleshooting item.
yellow= temporary use not good as new condition. green= Rfi spare part.
I leave card on item if possible unless green, and record info.
Then with machinery up and producing, I start with removed item If I cant repair and get a RFI new quality part I buy replacment.
We do this all day every day. what messes up the soup is when bean counters try to mandate this with a formula based upon mfgr. perfect testing conditions.
How many recalls did Toyota have last year?
Ill bet all those parts were tested good for 100000miles/ ten years service life by factory.
This is where reallity and murpheys law hit bean counters formulas at Toyota last year.
I would like to believe thier tests were as scientific and comprehensive as they could be.
Yet look at all the recalls!