Graham is not a real heavy chewer. I have booda velvets that he will chew on for an hour or so then he will leave it for a few days or so and then start to chew it for a couple of hours again. I would say that one booda velvet lasts at least 2-4 weeks. A watermellon flavored booda velvet that I bought him in June is all bumpy from his teeth marks, but it is still shaped like a bone, and he still chews on it. I guess Graham is one of those light chewers. I am not used to dogs that are heavier chewers then Graham, so I did not even realize those booda velvets could go so quickly. But then again...I have one medium sized dog and you have 3 large dogs and one small dog. I would expect that you go through chew toys alot faster with that ratio, too. Those booda velvets aren't cheap, either