WIP limits

See also: Flow, Teamwork

What it is

A work in progress limit caps how much a team has started and not finished. Every story in progress is unfinished value and a context someone has to hold in their head. Limiting it moves attention from starting work to finishing it.

Why the default is 1

Mainline's limit is per person, and it starts at one active story. A person working on two stories waits on both, and each one takes longer to reach users. At a limit of one, a blocked story is visible straight away, and the next move is to unblock it or to help someone else finish theirs.

The limit counts stories per person, so pairing and ensembles are unaffected. Several people can share one story, and it counts as one for each of them.

Enforced, in the transaction

Unlike the column limits in other tools, this one is enforced in the transaction that starts a story. It isn't displayed as a warning. Starting a story past the limit fails, and the person stays on the story they have.

Raising the limit

A team can raise its limit to a ceiling of 5. Changing it needs a reason, and the reason is recorded with the change as an event everyone on the team can see.

The Flow charts show what the change does to lead time, so the team can tell whether it helped.

Lowering the limit

Lowering the limit doesn't touch stories already in flight. Anyone over the new limit keeps what they have started, and can't start another story until they are under it.