Checking everything in your kit from time to time is a good idea. The shelf life of most things depends on how and where it is stored, the duct tape in my bob is in the factory package and stuffed in a zip lock. I live in Florida and the tape after a while will leave sticky everywhere if it is not wrapped well, so it gets replaced on a regular occasion. In a cooler climate i doubt that you would need to replace it as often. Also if you vacuum packed anything unpack it from time to time, i recently broke into my bob for a clean shirt, ripped open the vac package and the shirt had a nice musty odor to it. And no the packaging had not been broken. Of course it still smelled better than the shirt i was wearing.