Join Date: Dec 2010
Location: northern Deep South
Bikes: Fuji Touring, Novara Randonee
I'm probably half way through my box of 100 Rema patches, and they're still doing fine after about 10 years.
One thing that surely helps is Rema faces the active side of their patches with aluminum foil, meaning any moisture or oxygen has to diffuse from the back side (and through the plastic on the back). Also FWIW, mine stay in a heated/air conditioned utility room, so they are only exposed to perhaps 15F temperature change over a year. I don't know how 100F temperature and 100% RH swings might affect the remaining patches if I kept them in the garage.