I have about 30 tins open at the moment and they never go dry. I store my open tins in special containers that keep the tobacco fresh for at least a year and a half. I normally have 20-25 open at a time but I had a hankering for a special few tins so I opened them and now I am at 30 open tins. Within 2 weeks I will be back down to 20-25 open tins.
I forgot to add a pic of the plastic tubs I use. The Opaque containers with the white tops are what keep my tobacco fresh for so long. I got them at Walmarts in a 4-6 pack, I forget as it has been so long. I think it was 6 bucks for the 6 pack, only thing I know it was dirt cheap.