[dsr_]

The optimal number of loads of laundry is whatever rate keeps you in clean clothes within bounds with which you are comfortable.

There are people who are comfortable with the zero margin of wearing their last clean clothes while doing laundry. There are people who are unhappy when they get close to that. And there are people who want to be at the top border, where no more than one or two days' wear can be allowed to be unclean at a time.

The important thing for a marriage is that you are both happy with similar rates, or that you are both happy with your partner's rate even though it is not your own.

[afarrell]

Right. Notice the language you are using: "happy", "comfortable". Those are emotion words like "trust".

[dsr_]

That's because life is not solely a series of numeric optimization problems; objectivity is a useful tool, but people's desires are by definition subjective.