While it's almost possible to rebuild an entire car with NOS parts, I am wondering if there are some parts that should always be restored / repaired if possible vs. replaced, and if there are parts where it typically makes sense to simply replace vs. repair.

I know this is a loaded questions, subject to plenty of variables and opinions, but wondering if there are some parts for which there is general consensus.

Personally I always try to save a original GM part vs having to buy a repo and then having to spend hours trying to make the part fit correctly. Unless its a floor pan, trunk pan, wheel house, bumpers ect. I always repair and polish Gm Stainless vs buying repo chrome that does not fit.