Winter covers for above ground pools are one of those things where you get what you pay for — up to a point, and then not really. The PCO822 sits in the middle of Swimline's lineup, which is honestly where most 18-foot round pool owners end up anyway. Four feet of overlap is enough to secure it right, the 7x7 scrim keeps debris out without being overkill, and the blue/black construction blocks enough light to keep algae from getting a head start while the pool's closed. We've sold a lot of these.

My last cover only lasted two seasons — what am I actually supposed to do differently?

Usually it's standing water. A solid cover doesn't drain — whatever lands on top stays there, and a few inches of water sitting on it for weeks, especially if it freezes, is what kills covers early. Grab a cover pump when you order this. Cheap insurance.