For me, It's less about the water being clean / crystal clear the next year but more about the Intex poles and frame rusting. I always take mine down, clean off any rust and spray paint each pole. The pool is used only about 3 months so there's no reason to keep it the remaining 9 months unused, letting it rust away. I also feel safer without the pool there over the winter and the kids playing outside. It is a huge pain in the @$$ to take it down and redo it each year though. Either way, these Intex type pools aren't made to last forever.