for many years with no discernible loss of output. I once pulled the truck up to the boat at night, in the yard, and didn't notice one of the panels had blown off and was now "runned over" . I backed up the truck, wiped off the panel and the next day it was as happy as ever - try that with the new ridged frames. I like the fact that they are light and portable - easy to move to take advantage of available light. We store ours flat, up against the v-berth sides when not in use - they also fit nicely under the cushions. I have a big ridged frame panel but can't bring myself to actually mount it on the boat when these work so well.