I sure wouldn't expect them to go to pieces in just three years!! I just replaced the topper fabric on both slides on my 2003 Ultimate in May when the stitcing began to fall out. Mine are Carefree, with an aluminum shield they roll into when stowed. I removed the fabric and took it to an awning shop south of Dallas, had them confirm measurements (I would do them just a tad wider if I were doing it again!!), picked out fabric from their choices, and picked up the new toppers a couple of days later. I considered just having them stitched since that was the only real problem, but decided to go ahead and replace them as there were some small tears at the corners. The new ones were close to 1/2 the price it would have been to order and ship from Carefree, and I probably got better fabric this way.
Paul (KE5LXU) ...was fulltimin', now parttimin'
'03 Winnebago UA 40e / '05 Honda Odyssey toad