Sirspeedy, the effects of corrosion can be reduced by proper care. The tin plate on a good tube socket for example can reliably last for 30-40 years. OTOH if you store it in the basement or the garage where it can be attacked by humidity or moisture, the life of the connectors and filter capacitors can be really shortened.
If you stored a Martin (never a good thing for a string instrument as you know) it would suffer too. What's the saying? there's no free lunch? no free cigar?