This product is great for replacing valve stems more frequently, but certainly not as a substitute for proper maintenance. While the instructions present it as easy to use, it can be difficult to use. I see it as a very special tool, perfect for very specific needs. This is not a tool for "correct" valve stem replacement. I bought it for a specific need and used it twice. While it fills that need, I find it quite expensive and not the best quality. My biggest quality issue is the insert tube which is a key part of this kit. and my second problem is with the old stock puller tool. The intake pipe just doesn't seem strong to me. It fit well when I used it but didn't feel like a quality tool that would last many times as I felt it could break easily. The puller for the old stem has a very simple design which I thought could have taken more time to develop. While it works, I felt like it could work a lot better with more effort. If you need something to replace a standard car valve stem, look elsewhere. If you need something for emergency maintenance or even the apps on farms where maintenance is usually done while working, it might be worth your while. As a DIYer with limited needs, I don't see the value in this product.