I have repurchased this harness too many times to count. We replace after heavy wear and tear or after a chewing incident. I have two 60 lb lab mixes who are both pullers, strong, and too smart for their own good. Both of my dogs when put in traditional harnesses know they can slip out by putting it in reverse and ducking their heads but the second clasp around their lower rib cage prevents them from slipping out of the Ruffwear flagline harnesses. These are super durable, we only replace out of caution and concern that the crazy pulling could cause a break of the metal clasp from the harness but haven't had an issue.