I don't actually OWN a pair of pantyhose, just a few pairs of tights. So I guess we know what my answer is.
I wear tights in cold weather. I do not wear them during warm weather - I'd rather have bare legs. The only reason I'd wear pantyhose would be if I had some bruises/scrapes to cover up from my adventures.
Maybe it is a regional thing. Or an upbringing thing. My mom never bought me pantyhose when I was growing up. I've never been in a position where I've been expected to wear pantyhose.. even as a professional in DC, the women wearing skirts generally had bare legs.
I do, however, wear fishnets or stockings on occasion. Those would be "special" occasions, I think.