Hi,
I've had emailcontact with a maintenance specialist here in the Netherlands for Tag Heuer watches and he told me that Quartz and mechanical watches from Tag Heuer need maintenance every 5-6 years and that the costs (here in the Netherlands) would be around 660 dollars for mechanical and half of that for Quartz. He also told me that the cal. 16 is a very reliable mechanism.
Furthermore, after a few nights of sleep, I think that maybe 60 years is a long time for one watch and I owe myself a new (extra) watch when we are married for twelve and a half years!
To be continued 😉