There’s nothing consumers like better than freebies, which may be part of the reason frequent flyer programs are so popular.

But as a consumer, you want to get the best value for your long-term investment in their service—especially when roughly seven percent of all airline flights are paid for with points or miles, according to accounting firm PricewaterhouseCoopers.

To help consumer decide on a rewards plan, WalletHub compared 10 of the largest domestic airlines’ frequent flyer programs across 23 key metrics, ranging from the value of a rewards points per mile to blackout-date policies. 

One of the trends uncovered in the study was that airlines, in general,  are lowering the value that consumers are reaping from their flying miles. "Only three of the 10 largest airlines are offering more rewards value in 2019 than in 2018, sweetening the pot by an average of 13 percent," WalletHub said.

The following rewards programs, in ascending order, have been ranked by WalletHub as giving consumers the best value:

10.  Spirit Airlines – Free Spirit

Spirit Airlines, headquartered in Miramar, Fla., is the seventh-largest airline in the U.S. Spirit offers flyers low-cost airfare and none of the frills. Its Free Spirit frequent flyer program, for example, does not partner with other airlines, and if you don’t use your rewards, they’ll expire.