I get poison ivy really bad, so when I hike I wear my gaiters and long sleeve shirts. To keep me from getting too hot I wear the gaiters with shorts and i wear the long sleeve shirt unbuttoned. I can honestly say, since I bought these gaiters I have not had any poison ivy...that is about 2 years.
I also wear the gaiters when i hike in the winter, again with shorts. I never really get cold legs because I keep warm enough by hiking. If I do get chilly legs, I pull up my wool socks so that my entire calve is covered with my wool sock and gaiters.