"I almost never write reviews, but was so excited about this product, I decided to take a moment. My 30 pound dog is 12 years old and we have literally walked well over 10,000 miles over his lifetime. Walk everyday, and we both love it. In past year, he has struggled a lot, to the point we not only walked so slowly, but barely walked a mile or 2 each day, which took forever. There were even days he was not excited to go, and went a bit reluctantly."