Body Parts Repair or Replace

[FordV8]

So I was wondering what you guys thought about repairing or replacing body parts? I would think a lot of cars may have had body panels replaced in their lifetime so it really doesn't matter. On my 85 NCHP car the doors and trunk all have some rust. They are repairable but I already have rust free doors and a trunk I could use. The current doors have some reflective tape on them from its in service days and the trunk lid has some holes from equipment being mounted. But the tape would be sanded off when the car is painted. I will have no choice but to replace the passenger inner fender since it is all rotted due to battery acid.