I admire the author. He seems to have the focus, work ethic, and vision of someone ten years older. However, I think the thing to realize is this lifestyle necessitates a healthy existence: physical health, financially healthy, healthy relationships with friends and family, a healthy mental state.

Don't take those for granted. As you get older they require more investment in order to sustain you. I'm only 41 and it already feels like properly taking care of myself is at least 10h/week (workouts + cooking healthy food) atop of 8h/day of sleep.

I think the thing I'd be most concerned about is the large amount of time spent on-keyboard and RSI.