If you go out a lot, the last thing you want is for a friend to tell you that your mascara looks bad. I prevent that from happening, always carry a small cosmetic mirror with you. It's a small item to remember, but it can save you a lot of embarrassment. A cosmetic mirror usually folds up with a plastic cover, so there's not much chance of it getting scratched on your keys or other sharp items in your purse. Some of the best cosmetic mirrors will also have a space to hold makeup so you don't need to search for so many things in your purse.