Sam,

I assume with TT dials - those just drifted out of proper food frequency tune. I never had it on 2565/2564 sets, but very often on Princess dials. In this case I re-tune the coils with frequency meter which takes 5 minutes. Never had really “dead” TT dial.

Lamps is a kind of obvious consumable, so I have some stock of 100+ 51A lamps in case the next 50 years I have some of those burnt out.