“You take a step back and you say: when my customers come to me, what is the ongoing problem they're trying to solve or the ongoing goal they're trying to achieve? And then you design the features and benefits to support them forever on their journey.”

Build a "forever promise" around the ongoing goal your subscriber is always trying to solve

Every successful subscription is anchored to an ongoing human problem, not a one-time transaction. Netflix's forever promise is 'the biggest selection of professionally created video content in the most efficient way.' VSCO's is 'make your best photos better.' Defining your forever promise first forces you to cut features that serve the product's elegance rather than the customer's ongoing need.