if he is an aggresive chewer they will not last long. Even my sell agressive chewer can finish them off fairly quickily, but the do last longer than rawhide. they are certainly not as durable as the same size nylabone. If the traditional large lylabone is only holding up for a week long it to the Galileo bone by them the unique design makes it invredibly durable. Be sure to size it proberly as well. a small increase in sizw can have an amacing effect on strength. Size chart I would start with the "souper" size.
For Natural Chews cow hooves last the best for me, but the can smell bad and one has to be careful because the can break of sharp shards and pieces that are large enough that they are not likely to be digestable.