Premium Duo is essentially cheaper than buying two separate Premium accounts for €9.99 ($9.99 in the US) each per month or a family plan for five accounts for €14.99 per month. The big caveat, however, is you have to be living with someone to access it. That makes it ideal for flatmates and couples, though students should stick with the student plan, which is still the cheapest at $4.99 (and comes bundled with Hulu and Showtime in the US).
"The pilot for Premium Duo is part of Spotify's commitment to continuously explore new ways to improve the Premium experience.," a Spotify spokesperson said in a statement. "We routinely run a number of pilots and programs to improve our user experience, which can pave the path for broader changes to our product or just give us important learnings."
Of course, you can already team up with others on collaborative playlists on desktop or mobile. And, if you tend to ignore Spotify's algorithmic suggestions, then you'll probably shun the Duo Mix, too -- though it adds a human element (your friend's faves!) to the discovery process. But the real draw here is the price and the ability to keep two separate accounts with some convergence, if you want it. Best of all, you no longer have to jump through the hoops that come with password sharing, chiefly having to go offline (and stick to your Spotify downloads) when someone else comes on.