A few years ago, some friends had a "come to Jesus" talk with me when they helped me unpack and found tons of clothing I thought would "maybe be fun" to wear "someday" but that I had barely touched. Since then, my general rule for buying any new clothes or shoes is that I have to think of at least three different outfits I could put together with clothes I already own. If at least three viable possibilities don't happen immediately and if I find myself having to think too hard, I put it back.
For registering, I upped that number to 5: 5 different times in the last year when either an upgrade or a new item would have made some aspect of cooking, entertaining, grilling, making coffee, etc. significantly better/more enjoyable/easier. If I'm going into "well, maybe it would be fun to..." then off it goes unless it's something FI is really set on. This kept the snacks on a stick device away (yes you can buy a machine that is exclusively devoted to making snacks on a stick!!), but also made the 12-cup French press a no-brainer to add. Our crowd are boxed gift folks and we were getting asked where we registered mere days after getting engaged so I wanted to have a good variety for people to choose from but also not go overboard just for the sake of adding more stuff.
Was there anything you got that you'd thought you would use a lot but rarely did? Or something you got that you ended up using a lot more than you anticipated? Or something not from your registry that you didn't think you would ever want but surprisingly ended up getting a lot of use out of? Any surprises?
ETA: Ok, I lied. I don't always use the 3-outfits rule. The patent leather knee-length stilleto Guess boots in my closet are what happens when I don't and when DSW has a huge sale. But I still hold on to them because I did wear them for all of two minutes when FI and I dressed up as Jersey Shore cast members one Halloween and I think what if there's another costume that they'll be needed for someday :P