Cot matress in perfect condition, does it have to be replaced?

[~Hestia~]

I was planning on using Moo's mattress for Buster...put it outside to catch some sun and we had a very heavy and unexpected downpour! So ended up buying a new one

[OceanPrincess]

I've got the original cot mattress from DD... It's 3.5yrs old... We've never washed it or anything...