Quote Originally Posted by JHarri31
1. How often do they have to be replaced?
2. It seems much more economical to buy a bunch up front (1/2 or 1 lb. bags), but is it possible to store them w/o "using them up"
Since they last forever, it doesn't make much sense to buy more than you need. You don't need to store some with the intent to replace the ones in your humidor. It seems like they only need to be replaced if they absorb gunk from tap water. That's why they require distilled water only.

I bought the 1/2 ounce humitube, and it works fine in my desktop humidor.