My 12" gso coating is approx 5+ years old
I used to live quite close to the beach and probably more often than I realised there was a fair bit of salty air floating around at times.
The coating is definately showing signs of time , but is still very much usable and in probably another 3/4 years would still be .
10 " scopes pop up now and then with minimal use , but still used
but then your buying at a reduced price arn't you ?
good luck