Enroll in AA dining. The number of participating restaurants is pretty small, but you only need to (randomly) hit one every 18 months. It does help to set a reminder on your calender a few months before expiration. I remember some years ago I think I had Southwest miles expiring for both my wife and I, there was a Burger King that participated and I went and bought a cup of coffee with one credit card and a hashbrowns with another.