The day/nite shades my motorhome came with (4), the strings were constantly breaking. Under the warranty, my dealer re-strung them. 3 times.
Found out that after the warranty was over, it would cost me 90 bucks (1 hour labor) to do the job. No way. I went to "Blinds to Go". Had them make 4 "mini-shades", (same sizes, of course). They work fine and look great. And....only $130 !
The little plastic anchors break once in a while, but "Blinds to Go" has no problem giving me replacements. In fact, the lady gave me a bag of 12! That'll keep me forever!