Airline miles have an annoying habit: they expire quietly, and you only notice when you finally want to use them. Most programs expire miles after a period of account inactivity, often somewhere between eighteen and thirty-six months depending on the airline. The good news is that keeping miles alive rarely requires booking a flight. Almost any qualifying activity resets the clock.

First, learn your specific program's rule. Some airlines expire miles based on inactivity, others on a fixed age for each mile, and some do not expire miles at all. Log into your account and check the expiry policy and your miles' expiry dates. Programs usually show this in the account dashboard, though sometimes you have to dig. Knowing the rule — and the date — is half the battle, because most losses happen through simple forgetfulness rather than any deliberate policy trap.

The easiest reset is earning a small number of miles. Airline shopping portals let you earn miles on purchases you were going to make anyway: click through the airline's portal to a retailer, complete the purchase, and the miles post within weeks. Dining programs work similarly — register a payment card, eat at a participating restaurant, and earn miles automatically. Even a single small transaction can reset the inactivity timer for the entire balance. If you hold the airline's co-branded credit card, regular spending keeps the account active by itself.

Redeeming a small amount also resets activity in many programs. Magazine subscriptions, small gift cards, or a few hundred miles donated to a charity partner can all count as qualifying activity. This is worth doing when your balance is small and close to expiry anyway — better to spend a few hundred miles than lose tens of thousands. Check your program's rules first, because not every redemption type counts as activity in every program.

Transferable bank points are another safety net. If your miles live in a program with harsh expiry rules, consider whether transferring a small amount from a credit card rewards program into the airline account resets activity. Similarly, some programs allow miles to be transferred between members, which can help consolidate small balances before they expire. Always confirm the transfer counts as qualifying activity before relying on it.

Finally, set a recurring reminder. Put a calendar event six months before your earliest miles expire, and make a habit of checking all your loyalty accounts twice a year. A ten-minute review every six months is enough to keep every balance alive. Miles are a slow-burning asset — they take years to accumulate and a moment of inattention to lose. A tiny bit of maintenance keeps them ready for the trip you actually want to take.

If you juggle miles across several airlines, a simple tracking habit helps. Keep a small spreadsheet with one row per program: the airline, your balance, the expiry rule, and the date of your last qualifying activity. Update it whenever you earn or redeem miles, and review it twice a year. Some travelers also use award-tracking apps that pull balances automatically, but a spreadsheet works fine and costs nothing. The key is that no balance should ever surprise you. While you are at it, check whether your programs allow family pooling — combining balances with a partner or family member can push a small balance over the threshold for a useful award, and can also rescue miles that would otherwise expire unused. Also remember that credit card points transferred into an airline program usually inherit that program's expiry rules, so do not transfer speculatively: keep flexible bank points where they are until you have a specific award in mind, and transfer only when you are ready to book. This one habit protects the value of every mile you have earned.