Whatever mechanical switch you have should last you forever.
The only thing(s) that may ever "wear out" on the mechanical switches would be the contact posts (from pitting) and the copper washer (from continually sanding it down).
As for the old original electrical switches, they create more of a problem as they require soldering and replacement of the tact switch on a more regular basis.
I don't think Steve will mind if I post Curtis' video on "how to care for you PS switch"
here....