This is our 16th season with an 18X36 vinyl liner.
DS was not yet 1yr when we had it put in, LOTS of FUN for him and his friends still!
It costs about $500/season for chemicals, electric.
Then heating costs, if you plan to have a heater get the Energy Star brand(we did and it saves on gas costs).
There are opening and closing costs, $250 each for us.
In the pools 12th year we had a new liner put in, a new pool pump, filter, pool light rewired and all the wiring redone, a new auto chlorine dispenser. I think that's it!
Initially, we had a Polaris installed (automatic vac) on a seperate line so it runs while the pool is filtering. It saves a lot of time and I highly recommend having one if you don't want to be out there vacuming the bottom just about every day.
We have had a lot of family gatherings and a lot of fun in that pool, I wouldn't trade it for anything! It looks pretty at night too with the pool light on, sitting around the chimenea and relaxing.
Good Luck with your decision!