Ponies don't usually wear clothes. In fact, there aren't any creatures that require clothes as a social norm. But as we know, ponies do use clothes for special events, self-expression or if they want to display their status. Some wear them for protection while working or for comfort. Here we see three representatives:


-Asante definitely wears clothing on the avant-garde side as self expression. This is certainly a tame outfit. I imagine her as dressing up in a new outfit every day like Ms. Frizz.


- Mezzanine gets cold easily and wears big coats. She also wears athletic clothes when she runs.


-Clarabelle is Canterlot elite, whether she appears that way or not, and she'll embrace this for a short while. She has a lot of money behind her (with her mother being the founder of Fillyscouts, and a former teen popstar) and can afford designer clothing and bags. She prefers tame, muted colors typically. She probably wears clothes just because she can afford them and has grown accustomed to it.