These really make me miserable - things like Tesco vouchers and 10% of your next order stuff.
I tend to stuff them in my purse or throw them away. I really hate pulling them out of my purse and finding they've expired....
I'd rather they didn't exist at all but wanted to ask people who are good at keeping/using them where you keep them and how you find time to look through them or organise it so you don't have to.