When replacing an in-ground vinyl swimming pool liner, there are many considerations to be taken into account. Replacing the pool liner can be a big investment, so it should be carefully considered, just as you would any other significant home improvement. And, as with other home improvement, the most important thing is to have your pool liner installed correctly, by professionals who know what they are doing, and who care about quality and workmanship. With proper installation and care, your liner will last many years, so it is critical that the preparation and installation is done correctly. The structure must be in good condition and clean before installing the new liner, and the pool must be precisely measured so that the liner fits perfectly. When you think about it, it's a matter of economics... I have seen poorly installed liners last a lot less than 3 years, and well installed and well maintained liners can last up to 20 years, with the average life being 8-10 years. The most important factors that determine the life of the liner are: Quality of the liner; don't go cheap, you will pay for it! Proper fit; the liner should fit snugly in corners and radiuses, and have a slight vertical stretch. The condition and preparation of the structure; It must be clean, smooth, and free of rust. All gaskets and faceplates should be replaced. Taking the time to properly install the liner - It should be installed so that it is tight in the corners, and adjusted so that there is even stretch throughout the liner. It should be wrinkle free. Lastly, and just as importantly, the care the liner receives after it is installed. Water chemistry and proper care are critical!