>>61089603
1800 year old silver that was used as currency still shows up looking like this sometimes.
Taking it out a few times a year and rubbing it does literally nothing, and the tarnish is a protective layer that actively forms and prevents the underlying silver from tarnishing / disappearing.

As long as you don't polish it it might get really dark, but will not lose a significant amount of silver content unless you take it out and clink it together regularly for every piece.
You might overall take like 1% by weight at most out of some coins fondling them daily.