I did finally get a chance to get up and look at the toppers and noticed the material is getting old and does have sign of cracking. So I'm just going to go ahead and replaced the fabric on all three toppers. I've watched the YouTube videos and it doesn't look that complicated.
For anybody who has changed these before, my three toppers don't have the aluminum cover so the fabric is just exposed to the elements when rolled up. That's a little odd as my main awning along with all the window awnings do have the aluminum cover. I don't know why National RV cheaped out on the slide toppers. Anyway, I looked at the most recommended company for replacing the topper fabric and they tell you how to measure and you are supposed to tell them if you have the aluminum cover or not. What I want to do is include the aliminum cover with the new fabric. Has anybody added the aliminum covers that didn't have them before? I assume they will work with the exsiting hardware? I'll call the company that sells the fabric on Monday and see what they say.