Approx longevity of clear panels?

I plan on combining with my galv corrugated roof on a storage shed, a couple of clear or opaque panels for a skylight of sorts. I realize a real skylight would be more desireable but due to the nature of my project (old shed being remodeled), I do not want to put any more money in to it than needed. My question is approx how many years could I expect from a clear panel? I'm in Idaho and these panels would be on a 10:12 roof pitch on the north side. Also, is there any one kind of material or color that I should be looking for? Thanks.