The bin is full because each person thought someone else would empty it. A general conversation about helping more may leave the same assumption in place.
Choose the specific task and talk about when it needs doing. Ask what arrangement fits the household, considering availability and ability. Decide who notices the need as well as who performs the task.
Make the handover workable
If responsibility rotates, agree on how the change is communicated. If someone cannot do it, decide how they will ask for another arrangement. Keep the agreement visible where that helps, without turning every household task into a formal report.
Review it after an ordinary week. A task may need a clearer trigger or a different distribution if schedules change. Avoid using one missed instance as proof that the whole arrangement is useless. Look at what happened and whether the people involved understood the same responsibility. The aim is a household task that gets handled through an agreement everyone can actually use.
