I talk to a lot of younger faculty who struggle balancing work and childcare, and sometimes pass on important professional opportunities as a result. When my first son was about to be born, I had a life-changing conversation with Peter Sarnak. I was living in NYC and teaching at Yale, commuting a few days a week. Unprompted, he said: “I’m going to give you some unsolicited advice. Take your entire salary and spend it on childcare. The cost of childcare won’t go up much, but if you prove good theorems, your salary will.” I was a young assistant professor making ~$90K. My wife was finishing a postdoc and about to start a cardiology fellowship. It had never even occurred to me that we could afford a full-time nanny. But I knew better than to ignore Peter’s advice. So we “splurged.” The nanny arrived at 8am. I handed her the baby and went to “work” (Starbucks), and worked as hard as I could until 6pm, when I went home to relieve her. It was a real cost at the time. But, as Peter predicted, it paid off. Even though someone else cared for our son (eventually, sons) most of the day, we still had real evenings and weekends together — feeding, reading, bathing, playing. As the oldest is now getting ready for high school, I don’t feel like we missed out on any bonding in those early years. And I indeed suffered many fewer professional losses than I would have otherwise. (That sabbatical in Paris will have to wait until they're in college...) I’m not as good as Peter at forcing advice on people. So I’ll just leave this here, in case it helps someone else as much as it helped me.