The time to replace a pool liner is when you have had enough of the liner. That sounds a little flippant, so what the heck does that mean? Well there are several reasons to replace a liner any of which are valid and all relate to you the owner. The first most common reason to replace a liner is the pool is leaking and will not stop. You have hired a diver and they cannot find any leaks and leaks and will not stop or there is a major cut in the liner. The next most common reason is the printed pattern on the liner is substantially faded or gone. This happens from UV light exposure and high chlorine levels over the years. Most people just hate looking at a faded liner and want to but vibrancy back in their pools appearance. Another scenario is the pool water chemistry has been poorly maintained and the liner is badly wrinkled. With chemistry there are two critical balances Total Alkalinity and Calcium Hardness. If the Total Alkalinity & pH are kept too low over to long a period of time the liner will wrinkle badly and this problem can only be corrected by replacing the liner. If the Calcium Hardness is maintained too low for to long a period of time the liner can become brittle to the point if you step on it the liner would crack. So it is recommended that you have your pool water professionally tested at least 3 times a pool season if your season is 6 months long and 6 times a year if you have a 12-month season. The least common reason is the people just hate the pool liner pattern and want something different. This can happen if someone buys a house and hates the liner pattern that is currently in the pool when they purchase the house so they replace it.

The average life of a liner is about 10 years. The longest I have ever heard of a pool liner lasting was 25 years this was an in ground pool, of course there was no pattern in the liner for the last 15 years but the owners did not care. So as you can see the time to replace the liner is your choice. Keep in mind when replacing a liner the thicker the liner the more resistant to punctures the liner will be. If you are in a cold climate you will need a really thick liner. Standard mil thickness on in ground pool liners is usually 20 mil, 27/28 mil, 30 mil and 40 mil.

For above ground pools life expectancy is 5-10 years. Liner thickness generally runs 16 mil, 20 mil, 22 mil and 27 mil.

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I'm definitely changing my liner, it's 16yrs old, the bottom last year was white, t least in the deep end. Do you recommend 20mil or the 20/27 mil. We live on Long Island if that makes any difference.

The foam only need to be replaced if it is is in bad shape. Try and go with a 27mil liner but anything that will put a hole in a 20mil liner will more than likely put a hole in the thickest of liners...

Tyvm the help is appreciated.