Backlog grooming is the process of adding new user stories to the backlog, re-prioritizing existing stories as needed, creating estimates, and deconstructing larger stories into smaller stories or tasks. Rather than grooming the backlog sporadically throughout an iteration, the team may hold a backlog grooming session once per iteration. Scrum Alliance founder Ken Schwaber recommends that teams allocate 5% of their time to revisiting and tending to the backlog.
Backlog grooming is the term favored by the Scrum Alliance, although Scrum co-founder Jeff McKenna and Australian CST Kane Mar prefer to call this ceremony Story Time, and still others call this Backlog Refinement.
Agile Requirements: User Stories, Backlogs, & Beyond – Ellen Gottesdiener at Agile 2015 [Agile Amped Podcast]