We have the red Large Kong for our adult yellow lab, she has had it for over a year. It is still in very good condition. Some times we put canned dog food in it & freeze it. We make homemade liver treats that we put in it. Our dog only chews or pays attention to the Kong if there is food in it, that she is trying to get out. Recently a dog trainer told me to get her interested in the Kong, I boil it in chicken broth (15 minutes) and that helps to flavor the Kong. Of course, I wonder if she'll chew it up then. We do have dog bones that came with marrow in em...which she likes but as soon as the middle stuff is gone she isn't as interested. Treats don't stay in the dog bone, they fall out too easily. Over the dog bone, we prefer the Kong, to put goodies inside. She seems to be an aggressive chewer for example with natural dog chews (such as bully sticks) but does not chew on our stuff (furniture, shoes/etc.)