My strategy is similar to Jester's for similar reasons. I burn easily enough that I must measure out my sun exposure carefully. As with many here, I dislike sunscreen and much prefer to cover up with lightweight clothing to prevent burning my skin. However, I do 'spend' my limited exposure time for part of each hiking day by wearing shorts, usually when I am hiking uphill under a load. I also prefer clothes as a shield against bugs and try to minimize my use of deet.

That's why zip-off pants have been the right choice for me. I know some people have problems with chafing and irritation at the hem where the lower leg zips onto the uppers shorts, but I always check this out carefully before I buy a pair and haven't had problems in that way. I'm happy with my system. it is flexible and is lighter weight than taking separate long pants + shorts, while delivering the same end results.