I've been using Boveda humidity packs for about a decade now. Once drying and curing is done, I make sure to store with a humidity pack. My harvests usually don't make it more than a year, so I can't speak for storage longer than that. I've had them dry out before when I've left them in the open, and re hydrated them after without issue; this is not recommended by the manufacturer though.
I'd recommend Boveda humidity packs to anyone looking to ensure their harvest stays at the optimal humidity.
I'd recommend Boveda humidity packs to anyone looking to ensure their harvest stays at the optimal humidity.