A book I have (Renovating Old Houses by George Nash) noted as an aside
in one sentence that plaster will only stay usable for around a year. I
just bought 100 lb. of plaster (50 lb. USG Struct-o-lite and 50 lb. USG
Diamond Veneer Finish plaster) and wonder if it will last longer if I
store it in air-tight containers and store in a cool location. When I
bought these last week I had no idea it wouldn't keep indefinitely. I
have a lot of plaster work to do, but may well not get around to 95% of
it for a year or longer. Anyone have experience with these things?
Thanks for any info.

Dan