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It was so simple with the old frequent flyer miles programs: Fly a mile, earn a mile. Then take all those earned miles and use them to go someplace fun, for free.

Today, though, more airlines are adopting the “spend a lot, get more miles” rule (including legacy carriers American, Delta and United. This clearly favors business travelers who buy last-minute tickets and pay those expensive last-minute prices.

More bad news: Airline miles didn’t used to expire, but more and more do. Notable exceptions include Delta and JetBlue, but remember: The rules for airline miles programs change all the time (often with little notice) so check those airline emails (or visit the website every now and then).

What Kind of Miles Earner Are You?

All of this complicates the matter of whether loyalty pays off or not. Asking yourself these questions will help:

  • Do you fly a lot – at least three or four times a month – with your company (or your trust fund) paying the tab for the expensive tickets?
  • Do you spend a lot on your flights and other purchases, paying with your airline miles credit card (for example, do you pay your utilities bill that way)?
  • Do you book flights with an airline-branded credit card?
  • Are you willing to redeem miles for off-peak destinations?

In other words, know your fly/spend ratio: If you fly a lot, you’re on your way to earning a significant number of miles. But if you shop carefully and purchase domestic tickets at least a month before take-off, you won’t get the biggest bang for your buck in a lot of programs. Fortunately there are a few things you can do.

How to Get More for Your Miles

1. Use a miles-earning credit card: Many airline-branded cards earn bonus miles and some offer a wide selection ranging from free cards to cards with annual fees of $450. If the latter doesn’t sound enticing, many of these expensive cards offer other perks. For example, American’s Elite MasterCard offers access to faster security (priceless given today’s long TSA lines). Note: If you don’t earn enough miles for redemption, it might be smarter to forego the airline card altogether in favor of a cash-back card.

2. Be flexible on travel: Combine the lower miles-earning power of leisure travelers with airline capacity cuts over the past few years (fewer empty seats), and some airline awards seats to popular destinations at peak travel times are out of reach for all but the most elite members. Use your miles where others don’t want to go – or go when other don’t want to.

3. Keep your eye out for bonus promotions: American dropped the traditional fare sales in favor of bonus miles deals. The right one could put a traveler firmly on the path to redemption.

4. Become a hobbyist: If you’ve got the time, this can be worthwhile, but true rewards only come to those who fly a lot or spend a lot on a credit cards. Step one is determining which miles program is right for you and at the moment Southwest’s Rapid Rewards is winning all the accolades (additional bonus: Southwest’s new Caribbean routes). Of course, if Southwest isn’t in your city or can’t take you where you need to go, look for another program. Helpful online resources include NerdWallet, especially good for credit card comparisons; The Points Guy for all things miles; and FlyerTalk, where veteran travelers and elite miles members answer questions.

5. When in doubt, join them all: Signing up for a miles program costs you nothing. Even if you can’t use miles to redeem a trip or earn enough for an upgrade, it may have intangible benefits. We’ve heard anecdotal evidence that it can make a difference to an airline rep who is faced with the problem of choosing between two equally deserving delayed passengers vying for the same last seat on the next flight out. If one is a member of the airline’s miles program and one is not, who do you think wins?

Rick Seaney is the CEO and cofounder of FareCompare.