My 10" f5 GSO mirror is now 10 years old and is covered in tiny white spots & pinholes. No where near as bright and reflective as when new, even after washing. Probably at a level where it is noticeable at the eyepiece.
The trouble is it seems that it is cheaper to buy another mirror and have it shipped over than shipping it both ways for re-coating. If I knew I had an outstanding mirror (which I doubt), then it might be worth it. A recoat however may be more durable and better than the old one was when knew.
Not sure what is the best way to go.