The "One comes, one goes" rule

I stumbled across this lately, "Shwopping". I think it is a brilliant idea.

https://www.theguardian.com/money/2012/apr/26/marks-spencer-shwopping-scheme

So I decided, that's my new rule (like an addendum to the Make and Mend Challenge). I am calling it the "One comes, one goes" rule: If I buy/sew/get a new item, one item from my existing wardrobe has to go. Because I want my wardrobe to stay the way it is (or get lighter even...). 

Here's why I think it is a  gread idea:

• It makes you realize that you actually have a similar piece in your wardrobe
• It makes you think about whether that new piece is actually so much better than what you have already
• Which then makes you more aware of what you own. 
• Your wardrobe doesn't grow and grow and grow
• It also makes you think twice about accepting clothes gift.

 I think it is interesting that Marks&Spencer doesn't seem to worry about people then not buying anything, but shopping is so popular it probably doesn't even occur to people not to go shopping for leisure.