You're Bored With Your Wardrobe
If you wake up in the morning, look in your closet, and think "I hate all of this." You probably need to figure out how you want to look. It goes back to examining your favorite pieces, looking at other things from those designers, or similar collections, and then deciding the kinds of stuff actually worth dropping cash on.
Think about the notion of cost-per-wear. Sure, you might be feeling that leopard-print button down right now, but could you see yourself wearing it six months down the line? Or even more than once a week?