Boveda packages are to help keep your tobacco at the perfect humidity. It can add or remove humidity depending on the temperature. It also does great to help prevent molding, and it is all purified water that is being emitted.
How to tell you need to change your Boveda package..
When it is dry and crispy, it is time to replace. The more you use, the longer they last.
It has a 2-6 month usage depending on the exposure to air it gets.
If it is not removed from its package it has a 2 year shelf life