Refinement, story splitting, story points versus absolutes, planning poker, and forecasting.
3 questions in Agile, Scrum & Delivery.
Treat the backlog as inventory with a carrying cost, delete rather than archive the items nobody will ever order, and derive how deep to refine from the team's measured throughput instead of refining everything. Refinement that clarifies nothing is usually missing a decision, not a better format.
Split vertically, so each slice goes end to end and delivers something demonstrable, using patterns such as workflow steps, business-rule variations, happy path first, and data or interface variants. Splitting by layer or by half a Sprint is not splitting - it produces work that cannot be reviewed or shipped.
Points are relative sizes that trade false precision for a fast conversation whose real output is surfaced disagreement. Estimates that are always wrong are a system symptom, so diagnose unclear criteria, oversized stories, invisible work and interruptions, then forecast with throughput and cycle time.