Worn out boilers

Question is: are the '90s boilers any more "worn out" than the '80's boilers. Yes, they are older, but why fab a new boiler unless it is really necessary? Nobody on the D&S or the C&TS is going to (or be allowed to) restore a locomotive using a "bad" boiler. Also consider that some of the K-36 engine boilers have had many "boiler hours" put on them since the end of service on the D&RGW, while the K-37 boilers have been "resting". Assuming steps have been taken to mitigate corrosion on the inactive locomotives, perhaps the effective age of the K-36 and K-37 boilers may not be that far apart??????
Just speculating, Scott