Loyalty programs offer a powerful incentive to travel, and to travel more. But is there a downside? Here's everything you need to know.

The ultimate guide to travel loyalty programs

Loyalty programs offer a powerful incentive to travel, and to travel more. Since the first frequent flier programs appeared in the early 1980s, frequent flier and frequent stayer incentives have mushroomed to proportions no one could have predicted. Today, it’s possible to collect miles without darkening the door of an aircraft, or points without checking into a hotel. You can earn them from buying groceries or subscribing to Netflix.