Fibonacci vs T-shirt sizes — which deck for which team?

The short version

If your stories are mostly < 13 points, Fibonacci gives useful resolution. If your team is allergic to false precision, T-shirt sizes (XS → XXL) is liberating.

When Fibonacci shines

• Mature backlog, fairly homogeneous story sizes
• You actually compare velocity over time
• Re-estimating mid-sprint is rare

When T-shirts shine

• Fresh product, scope is fuzzy
• You estimate in hours later, not story points
• Discussions about "is this 5 or 8" are draining

Mix and match

Different games can use different decks. Discovery sessions in T-shirts, sprint planning in Fibonacci.