Hello Knarf - I think Cowboy Casey is right that much depends on the initial quality (i.e. thickness) of the liner and also how well it has been taken care of. You might be pushing it at 10 years, but it could also last another 5+, so can't say with much certainty if you are getting near the end of its useful life.
I am in your general area (in Darien) and replaced mine last year so will share my experience. I had re-patched my liner in one spot (it was patched when I bought the home), but sometime during the closed season (winter 2014/spring 2015) I noticed the water level had dropped to right around that patch. Ok, time for another re-patch, freezing temps, ice whatever must have taken its toll. When I tore off the remains of the old patch it ripped a good size section of the liner as well. Not un-patchable, but pretty big. I also noticed it had felt pretty brittle in some spots so, given that I did not know the age of the liner (but suspected it could be up to 10 years old), I decided to just replace in the spring rather than risk having to do so mid-summer, plus there were some major wrinkles on the floor and faded areas I was sick of looking at. I am glad I did, as I tore out the old liner, there was some really brittle sections!
I did call around the area to see on costs of replacement, most places I called it was around $1000 and they wanted me to buy the liner from them. With inspiration and help from this board I realized I could do it myself and would prefer to choose from all the liners on the internet rather than the 4-5 options from pro install places.
I literally did the job myself, no helping hands. I had planned on having a few friends over and paying them in beer, but when my new liner arrived, I got really motivated and took a couple of days off work and knocked it out.
So, it is definitely a DIY job if you are so inclined - I had never done anything like this before. I watched lots of you tube videos on the subject and ran into a few challenges along the way, but nothing insurmountable, especially with the support of this forum.
Here are a couple of threads you may want to read:
My decision process to go with a new liner:
Time for a new liner??
My thread on the actual replacement:
Help Paul install his new liner
Post back with any questions.
