must-have

From must +‎ have.

must-have

1. Essential to own.
   • 2003 December 15, The New Yorker, page 69:

     The must-have toy is the apotheosis of the marketing of toys as fashion accessories.

must-have (plural must-haves)

1. An item that one must own, or a feature that is essential to a service, etc.

   Coordinate term: nice-to-have

   The selfie-stick is this year's must-have.

   • 2021, Steven S. Hoffman, Surviving a Startup, HarperCollins, →ISBN, page 58:

     There's a huge gulf between “must-have” and “nice-to-have” products. If you sell a nice-to-have product, no one, not even your best friends, will use it long term. We all focus on must-haves.