Deer & Deer Hunting Magazine had a good article on carbon clothing two issues back. I use carbon clothing and I know that it works as long as Ipractice scent control. It's not 100%, but it's an added advantage. As for how long it's good for, I still use a suit I bought in 1999, I wash and dry it at the beginning, once during and at the end of the season, I then seal it in a scent proof bag. I don't beleive that when the manufactures tell you to recharge it in the dryer, they intend for you to completely recharge it as Kevin1 indicates. I KNOW THEY WORK FROM MY EXPERIANCE AS WELL AS OTHERS IN OUR CAMP. I have never heard anyone who has used carbon complain about it not working.