Miles expiration is a quiet loss: balances can vanish after a period of inactivity or on a fixed schedule, often discovered only when you try to book a trip.

Most programmes use an inactivity rule of twelve to thirty-six months. Any earning or redeeming activity, however small, usually resets the clock for the whole balance.

A tiny shopping portal purchase, a dining programme meal, or a small bank points transfer twice a year is enough to keep most balances alive indefinitely.

For long-term safety, consolidate earning into one or two programmes you actually use, track balances twice a year, and keep everyday points in transferable bank programmes.