Overall, yes, used golf balls are good. Im sure whenever you're on the golf course digging around in the trees to find your ball, you've come across a few others in there too. These are absolutely fine to use. The only used golf ball we'd recommend avoiding are used balls from eBay or lake balls - after just 12 hours in the water, a golf ball is ruined - stick to used balls on Amazon or ones that you find on the course.