My family has rules and positions we vote on. We’re all adults out of the parents’ house. We collaborate on a lot of projects and travel together in different combinations; the rules, or guidelines really, make us more efficient.
I am often travel coordinator for joint trips. Someone else handles food coordination specifically. The youngest calls meetings, usually on a quarterly to yearly cadence, and publishes the meeting notes to a shared cloud drive. Another is in charge of coordinating a Christmas gift exchange. We’ve rotated being financial and medical backup/adviser to the parents and those roles also comes with responsibility to update the other siblings on major changes.