KyDan, I have loosened the strings on my blinds and they seem to work much easier, but it is sort of a fine line between falling and working easy. I think we are getting better at adjustments, though. I am hoping maybe we have extended the life of each stringing by "de-stressing" them.
You raised the possibility that UV exposure may play a role, and I think that could present a valid concern in my case, too, since my port/OD side (where most of the windows are found on my rig with the atrium feature) certainly takes a lot of sun when in the drive at home. Time will tell.
Most importantly, like most things rv, my concern over this has fallen off several decibels after a successful camping trip last weekend where my repairs (and adjustments) seemed to work. I guess both my blind strings and I have been de-stressed.
I have not yet purchased those replacement end caps (or the color-coordinated duct tape), but will eventually get a supply to tidy up those I mangled.