How to get the most value from your miles

You can think of valuable awards in two ways. The first is those awards in which you get the highest-priced reward for the fewest miles. The second is any award that has incredible value to you, regardless of its financial worth.

Frequent flyers have long touted upgrades as the most valuable awards. The price differential between coach and first class is huge, but the number of miles you need for an upgrade is not. Miles used to upgrade an economy flight are therefore worth more than the miles you pay for a free seat in coach. Just remember to factor in any extra fees for upgrading a discount economy ticket.

Walk-up fares are among the priciest tickets you can buy. If you need to make an 11th-hour reservation, miles can save you from emptying your bank account. You'll definitely get great value out of using your miles for a last-minute flight, but you may have to pay extra fees for late bookings on some airlines.

Sometimes, you just don't have the funds for another plane ticket, no matter how cheap the flight. Miles can be invaluable for getting you to your destination when otherwise you'd have to miss out on a special event or trip. A cheap fare may give you a low per-mile value, but the difference between getting out and staying home is worth whatever you spend.

Any award can be a great award if it's something you need or want. But certain mileage transactions give you a low value or even decrease the value of your miles.

A sale fare or discounted flight will never give you good value for your miles. You're better off paying cash for a domestic flight that costs $250 or less. If you use miles, they'll be worth less than the industry standard. To get better value, save your miles for high-priced tickets.

You can use Points.com and other programs to transfer miles from one airline to another. Just know that your miles will significantly decrease in value through the transaction. For example, if you want to convert American miles to Delta miles, you can do so through Hilton HHonors' reward exchange. Start with 5,000 American miles, and you'll end up with only 1,000 Delta miles. The Delta miles may be more useful to you, but they're worth 80 percent less than your original American miles.

Most airlines will give you the choice of spending twice as many miles to book any available seat with miles. These unrestricted awards can be a great option when you absolutely must pay with miles and the lower-priced awards aren't available. However, your miles will be worth half as much. If you want the best value, stick to restricted awards.