Okay, I’ll admit that signing up for an airline’s mileage/rewards program does come with a barrage of annoying promotional emails. BUT! The perks are worth it. Caitlin is a committed member to all of ’em. “Why? It’s free, and the more often you fly, the more miles you accumulate and the more perks you get,” she explains. Seriously, just by copying and pasting your email onto every airline’s loyalty sign-up page (for a whopping zero dollars, I might add), you can get free flights and free upgrades.