I see many people on the web recommending the use of desiccant packs to control moisture in stored foods. In over 40 years of storing food, I have never used one. Our dried storage includes all types of grains, legumes, dehydrated foods, both home dried and commercial. During this time, I have never had any foods damaged by moisture.
The whole trick is to make sure your products are dry before you package them. Dehydrated fruits, vegetables and meats should be dried to the point that they break when bent. Foods dried to this point and package properly (in moisture proof containers) should not need a desiccant. I have never seen a commercially dried long-term storage food with one in it.
The Mormon Church which has conducted extensive research into food storage does not recommend the use of desiccant packs. None of the manufactures of oxygen absorbers recommend the use of desiccant packs. In fact, some sources argue that they could be detrimental to your food storage. Some types of oxygen absorbers require a minimum amount of oxygen to work. Desiccant packs may drop the moisture level below this threshold.
Except in unusual cases with extremely high humidity, I would not use desiccant packs.