Prior to my pregnancy I liked leggings, during my pregnancy they allowed me to not have to wear maternity jeans and post pregnancy they allow me to not have to buy pants. Ever. Again. I wear LulaRoe leggings and if you are thinking about buying some (or something else) from them, check out my review. Save your "leggings aren't pants" comments because they are not welcome here.
Let me back track though, I fully believe that your rear should be covered while wearing leggings and they should fit you. If you put on a pair of leggings and they are stretched so thin they become almost see-through, don't wear them! I don't need to see the color underwear you're wearing just as you don't want to see mine.
The fall and winter make wearing leggings even easier because all you need are your trusty leggings and a sweater and BAM! you look put together (even if you haven't showered in two or three days).
So take my advice, get yourself some leggings. They are comfortable, they allow you to wear boots and sweaters without feeling too bulky in the colder months and they give you full range of motion to kick anyone who says leggings can't be worn as pants.