I use the Boveda packs for my desk top humidor. You are correct that they need to be replaced every 3 months. Carefull on the large box. They expire after a year. I use 72 in the winter and 65 in the summer. My humidor stays very steady with them. I also use beads 65, but only in my wine refrigerator that I turned into a humidor. They nice thing with the boveda packs is you can put them anywhere in the humidor. On top of the cigars, under them or beside them.