1. Division-of-labor, specialization of trade... although it might not fit every feminists' "equality of outcome, share everything" political-correctness, it doesn't make combined net income much sense (or cents) to risk a $300k income with sleeplessness/low-productivity vs. an $80k one if one spouse (assuming spouse isn't a lawyer, doctor or engineer) can be at home full-time, or both as full-time parents with parental leave policies/laws or take a sabbatical. Dumping/delegating mundane tasks onto a high income earner doesn't jive with common sense. Also, automate and delegate as much minutia as possible outside to contractors and domestic workers (cooking, cleaning, construction, yard-work etc.) of one's wheelhouse to have more family, couple & work time. If you make $80-$600/hour USD, don't waste your time doing low value tasks that others could do more cheaply for you.