I have three customers with Fairclough covers all over 20 years old. One is 23 years old one is 22 and one just turned 20. While all of them have had some thread patching or zipper replacments for the doors the main cover is intact and still fully operational.I have a Fairclough Cover made out of Cotton Duck. I have used it for 18 winters.
I have a number of other customers with Fairclough covers all over 15 years old. They key with the Fairclough is to take care of it and install it correctly. If it is religiously put away dry (BONE DRY) and kept away from moth & mice 20 years, even in harsh Maine winters is pretty doable. If you live in an area of heavy snow the snow struts are a MUST HAVE option!!
I would own a Fairclough in a heart beat but they refuse to build one for me that stops at the toe rail. Sorry but NOTHING touches my painted topsides....
Keep in mind the Fairclough is probably the best built and best fitting winter cover out there. If your frame etc. is not up to snuff no material is going to go the long haul regardless of the makers claims...