The weather, the time of day, indoors or outdoors, etc. Also, what color tights?
In cold weather, I wouldn't expect a girl to be walking around with bare legs. That's kind of weird. But if it's a sunny day then bare legs are the way to go. And if it's a balmy night, then bare is probably still slightly preferable but either is good.
skirt bare legs with high boots, or srunched up long socks with trainers lol, because I think women have legs that express curves, they shape continuously as you walk, giving the on looker a instant hit of eye candy from the legs alone, and as we watch and go up the leg, it causes the imagination to wonder, an absolute pleasure to see women with their legs out lol,x