...thoughts, thanks for that Tom
My major dispute having maybe +50 watches is the cost of maintenance versus repairing the odd pieces that will fail.
Worst is as you mention the vintages that I can not so easily replace or find parts to. One answer for my self is on the special ones to find a watch where the housing, dial, hands, glas etc are missing or in bad shape. Thus keeping the calibre as part for later repairs. On one occasion this seems "easy" as a part of mycollection is now the calibre 560 counting for some 12 watches.
On the Omega Bienne I can also only answer,the cost might be "high" but if something is wrong they really fix it.
I also had a Seamsster that my local official dealer was going to repair. He came into a situation where there was misssing some parts and he took contact with Omega Bienne and received from them the parts free-of-charge (so he said at least)
Best
Hans