1. ALL slide toppers will accumulate rain and then you have to bring the slide in to remove the water. Don't do this and your slide material will stretch and make the problem worse
2. Slide Toppers also need to be cleaned/blown off of leaves and debris. Just retracting will not shed any debris. Pine Needles are the worst. They will retract inside the roller tube when you have a metal exterior cover and jam up the spring and not roll all the way tight
3. Slide covers are great for keeping water from getting inside the slide seals and coming in the RV. Granted the slide seal system SHOULD keep water out but why tempt fate on older rigs. Doug