how to extend life of solar lights?

Just bought some more cheap solar lights you put in your yard. These are stainless steel and Walgreens had 6 on clearance for $4!
Going to replace some plastic ones out in the yard where the small solar part has gotten weatherized from the blazing hot sun and stopped working.
Was wondering if there is any way to extend the life of these. For example, wondering if I could put clear plastic shipping tape over the solar panels and they would still work the same in charging the batteries and would protect them more. Anyone have experience with this? 

Oddly enough, what shortens the life of solar panels is the sun!  With equal light, they will produce more electricity at 70 degrees than they will at 90+ degrees.  The tape may trap more heat, therefore causing them to fail earlier than if left alone.  Since days are long, and nights are short this time of year, you might experiment putting a piece of window screen over them to filter the direct rays of the sun.  As the days shorten, you can simply remove the screen to get maximum charge for the longer nights ahead.

Thanks, makes sense to me!

make sure any you buy have replacement batteries avail..that goes for all battery operated items..including solar