Another thing to take away from that: hire someone with kids if you have the option. Maximum output of intellectual work is achieved with a 30-40 hour working week. The author settled on a 50+ hour working week, which is higher than optimum, enough to degrade her judgment and productivity - but only somewhat, not catastrophically; she was still able to get good work done. It's clear that without children, she would have settled on a substantially longer working week, probably enough to destroy her judgment and the quality of her work.