Airplanes operated for passenger transport are on a very controlled maintenance program. Almost all parts are numbered and tracked, including their age, flight

Airplanes operated for passenger transport are on a very controlled maintenance program. Almost all parts are numbered and tracked, including their age, flight hours and cycles (basically number of flights). You cannot replace even a bolt with another that isn't according to the same manufacturer spec and tracked in the same manner. So some screws could be the same spec, but in general you don't just pick one out of a bucket and screw it in.