You might not fly enough miles in a year to earn status with an airline (for the big ones, status normally starts at 25k miles plus a certain amount of dollars spent), but it's still important to pick one carrier and stick with it . . . and then save those miles! While a first-class flight to Europe typically costs thousands of dollars, it's usually much more attainable to book with miles. Be sure to learn your carrier's expiration policy, as some airlines have miles that never expire (while others do not).
Zachary Honig, editor-at-large at The Points Guy, advises travelers to be wary about using miles on shorter domestic flights, as the perks for an international upgrade are usually so much better. "While burning more miles might make sense now on a short domestic flight, an international business-class award will generally land you a lie-flat seat, getting you a solid meal and some quality sleep," he said.