If you use a release aid when shooting a bow and most bowhunters do, You should consider carrying an extra release while hunting.
Ideally, it should be identical to the release you're currently using, but any functional release that fits similar to your everyday model will work.
If you use a pack, put your extra release in there for the entire season. You may never need, but you never know when a release can break, you might accidentally drop it from your stand, or more commonly, just plain come up missing. So its always a good idea to have a backup plan in place and in this case an extra release at the ready.