I looked through my inventory the other day, and I was reminded of just how much stuff is in there, how many outfits sit waiting for me to wear again.
It's often pointed out that SL lacks one major incentive to buy more stuff: things don't wear out; you can't spill your virtual beverage on your virtual blouse and stain it irreparably. Walking in SL doesn't wear down the heels of your virtual shoes. (And it's not aerobic, either, darn it.) Your avatar doesn't gain weight unless you go out of your way to make it happen, and even if it does, SL's paint-on clothing will still paint your shape.
All I can say is, if I'm any example, clothiers don't have anything to worry about... but I will be pulling old outfits out of the virtual closet. They're still just as pretty as they were when I bought them.