They will be the last ones you will ever need. I do recommend you have extra track links though, depending on where and how you drive. If you get a stone caught in the tracks the only damage may be a broken link, my transmissions will not be affected in the least. They have survived 10 years in this rock garden we call home and have often been driven by young students at Battery Museum, albeit under one on one adult supervision. Still and all, children are children and things happen...but not to my units.