Does a vintage watch lose value if movement parts are replaced during service

[hungryturtle]

Two small movement parts were due for replacement with their modern equivalents but these are replaced with genuine Rolex/Zenith parts?
So does the above make the watch lose any value?

[Dan S]

Generally not a big deal, but there might be some exceptions for highly visible branded parts (e.g. a rotor or engraved bridge) or if the replacement parts are large and mismatched in color/finish. Even then, the reduction of value is small compared to that associated with replaced external parts like hands/dial/bezel-insert. When asking questions it's always best to be as specific as possible; what parts are you referring to?

[starlite29]

Agree w Dan. Certain parts such as mainsprings and case tubes wear with age and must be replaced to keep the watch functional. Pretty much all independent WMs will return the old parts on request which should mitigate any concerns with historically significant pieces. RSC obviously will not return parts but the factory service tends to offset the concern about originality anyway.

[hungryturtle]

crown wheel core Is the part

[Dan S]

Originally Posted by hungryturtle

crown wheel core Is the part

I wouldn't give that a moment's thought.

[TuRo]

No