I have a 1/3 Sopwith Pup with a G-62 that i don't fly very often, last time out they said it smelled like the gas was stale, my nose is not very sensitive and I could not tell the difference.
How much performance is likely to be lost with stale gas?
How often should you replace gas to insure it is fresh?

Get some Stabil at Lowes and it won't go stale.

Thanks for the tip, I see Lowes also has 2 stroke oil with the stabilizer already in it. I been using lawnmower oil but I see from the posts the guys are using different kinds, Amsoil, etc. What kind do you use?