im not an expert but I can tell you what works for us. And every pup is different. Some chew for what seems like years. Others never really chew at all. I like the chew sticks that are pressed. It's like bits of ground up rawhide pressed into a stick. They chip off pieces as they chew. If you do the true rawhide sticks just observe closely. They can chew long pieces into slimmy leather and try to swallow them. I've had to pull many out of Bella's mouth because she was choking. To the point I swear each time I will never give her a rawhide again. As pups the chipped sticks are great. As they get older it's harder to find something that lasts longer than 30 seconds. I found these pressed rings awhile ago. I get them at our local farm and garden store. I'm sure you can find online. But they are pressed rings. I love them. They last days! And they can't get big pieces off. It's small bits at a time. They are a rawhide. So they do leave white marks on the girls noses. Some vets say no rawhides at all. So please consult your vet. I have always given rawhides. But never unattended. The girls each get to chew one while we eat dinner. Then I take them away. This pic is of curly chewing hers. This ring is almost a week old. So a bargain at $3 each to keep them busy.