I'm a little like COBI in that it depends on what category of clothing we're talking about -
Work: 2 weeks - could be 3 if I wasn't so precious about the dresses I purposely bought to be suitable for work
and non-work. When I get dresses, I don't like wearing them too much because I don't want them going all scabby and bobbly from too much washing.
Weird I know, and I worked out the other day prob illogical 'cause one day in a few years I may decide I don't like them anymore/they just look really outta place with fashion trends so I'll have to ditch them and I'll only have worn them a little!
Non-work: 6 months - last year I had a major blitz of my wardrobe. I chucked anything that didn't get me feeling good and then I replaced it all over several months and bought tonnes of dresses.
But no tops hence the work one being so different (I normally wear top plus jeans for work).
For me clothes are really important in the way I feel about myself so whilst some would say I've wasted my money, I don't feel that way at all. If I end up with a walk-in wardrobe worth one day then that'd suit me down to the ground! Hey it's one of my hobbies!