If we allow people to freely sign up for tasks, there are likely to be certain tasks that no one may ever sign up to do. For example, people may be less likely to sign up for “washing dishes” than “baking bread.” Everyone can help out with these less-wanted tasks by random assignment. Perhaps, out of every year, each resident needs to spend two hours cheerfully cleaning dishes in a restaurant in order to get that task done for the new city. If no one really wants to wash dishes, say, we ask everyone to wash dishes for two hours per month or 2 hours per year (depending on the task) to spread out the load. It really would not be that big of a deal, because everyone shares these tasks.
