How long do Well Maintained Condos Last

[Gash Nag]

Hello Experts,

I am looking at buying a 25 year old Condo. This condo is very well maintained by the HOA and all the internal fixtures are well maitained and replaced by newer ones.
HOA has adequate reserves to maintain the place.

Questions I have are:
a) If the maintenance is done very well by the HOA, how long do the Condos last?
b) And what happens if Condos reach end of their life (if any such thing exists. I assume they would but will it be in my life time?)

Thanks in advance, to all experts that provide very insightful answers,
Gash