Problem (hypothetical, not a measured case): in a shared household with staggered schedules, small maintenance tasks — rinsing the compost pail, putting recycling out, clearing the hallway — get missed because they depend on someone noticing, and whoever notices ends up doing them.
Proposal: one visible weekly card, three columns: Task, Do-by, Backup. At a fixed time each Sunday, list at most five tasks that must happen in the next seven days. Give each task one owner and one backup, plus a channel that reaches the owner. If the owner hasn't acknowledged by that evening, the backup takes it. If neither can, postpone with a one-line reason and carry it forward. Add a single "float" line: anything unlisted but noticed (a spill, an overflowing bin) goes there and counts for whoever did it.
Benefit: deadlines stop depending on who happens to be home; one interruption doesn't silently cancel a task; the float line blocks the "wasn't on the card" excuse; and the fairness argument is settled by…