I just replaced both slide toppers. Well, one of them anyway, the other one I just cut off about 6" of material from the roof side that had the sun exposure and re-sewed it and reversed it on the roller so the part that had been rolled up is now at the roof rail.
Once I got the rollers un-rolled I used a super-duty zip tie to tie off the little arm to keep it from unrolling. Caution here, there's a LOT of spring tension so you have to hold on tight. If you let it go it could really hurt you or ruin your roller or cover. The factory says remove the rivets and all that garb, I figured why bother, my method worked out well enough to get the job done.
If you're experiencing flapping in winds under about 30mph consider putting one or two more winds on the roller spring. It's a PITA to do as you have to take the awning off to do it. Over 30-40mph it's prolly a good idea to retract the slides.
The factory fabric AE/Dometic puts on them is pretty cheezy. Most folks get at most four years on them and then they start delaminating and need replacement; and they're expensive.
I ordered some wonderful material from www.sailrite.com,
it's called BOAT TOPPING WHITE ON WHITE. It's just a bit heavier than the stock fabric but WAY nicer and a lot more heavy duty. I expect the new fabric will way out last the stock. BTW, it's less than half the cost of buying them already made up.
We have a Bernina sewing machine so I ordered #18 needles and some poly thread and it sewed the original rubber bolt-ropes in like butter. Turned out really nice and was not difficult at all to remount them. If you're handy this is a great way to replace them. I double-sewed them, straight stitch next to the bolt-rubber, and then a zig-zag just next to the first row of stiches. They are way strong and look professional.
I too would not run without toppers. But I have to agree the factory material leaves a lot to be desired.