In regards to restitching older fabric.
The determining factor when to restitch or buy new fabric rests solely on the fabric you currently have.
# 1 - Does it fit your slide well and cover the ends of the slide roof properly ? If not then you are wasting a bunch of time restitching a fabric that will not properly keep water off the roof of your slide ( which will go directly to interior floors of your coach ).
# 2 - How old is the fabric ? If it is 5 years or less and in good shape and covers the slide roof well then restitching is fine.
# 3 - If the fabric is close to 5 yrs old then you should do a water repellency test. Spray some water on your topper then check to see if any percolates through. If it does then the fibers have seperated and the fabric should be replaced.
I am all for coach owners saving money and restitching is one good way to do that. But I have seen guys restitch toppers that were too short or beyond their life expectancy and they ended up causing leaks inside the slides and cost them 4 times the money in repairs then if they would have just replaced the fabric.
It is very hard for me to tell someone if their fabric is OK to restitch without testing it, feeling it and looking at it. After a decade of experience I am pretty much spot on when I can see it in person. But over the internet it is impossible. I am sure you can all understand.
Chris T