Bandit's favorite doggie treats are the Porkhide Twists that come in bulk at Costco. I picked up a package during a shopping trip to Costco the first month we had Bandit. It was a great purchase as he loves them, and he has no less than eight of them going at one time in different places all over the house, upstairs and down, and all in various stages of uncoiling and destruction. He takes them outside too and chews on them in the rain. I feel like he's gone through tons of them, but we still have loads of them left.
When I notice them starting to look like this (and worse), I throw them out and replace them with fresh ones