Maybe this should be a sticky, to remind ourselves:

Thought this would be a nice reminder to start logging into your dormant airline and hotel accounts to see when your miles expire. If they expire this year, sign up for Idine under that airline, register your credit card and charge a small meal/lunch at a participating restaurant and this will re-activate your miles another three years.

If you need tips for how to keep your miles active, I'll list a few here:

AA: Idine, Opinionplace, Kelloggs miles, transfer from hotels: Starwood,
Priority Club, Hilton, car rental, hotel stay,

UA: Idine, car rental, hotel stay, transfer from hotels:Starwood, Priority Club,

NW: Idine, car rental, hotel stay, transfer from hotels: Starwood, Priority Club

DL: Idine. car rental, hotel stay, transfer from hotels: Starwood, Priority Club

CO: Idine?, car rental, hotel stay, transfer from hotels: Starwood, PC Club

Good luck...