As Mr_D said, sun and water are better controlled with 'slide toppers'. Personally, I don't want to get on my ladder or climb up on the roof with my broom to clear any small limbs, leaves or other debris off the slide roofs before I bring them in.... Don't need the hassle. Much nicer to have toppers do it for me, and they do a really good job. Wind has not been a huge issue, but if it gets bad (a little scary) I toss a nylon rope over, end-to-end, and hook 'em down rather gently with bungies under the slide. So far, that's worked fine.
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'07 Itasca 35L/W22 FULL-TIMING
1000 Trails - VFW - 5 Yrs Army
"NOT ALL WHO WANDER ARE LOST"