Absolutely not sustainable, and a recipe for massive regret both in the near term and later in life. In the near term this person will burn out. Later in life t

Absolutely not sustainable, and a recipe for massive regret both in the near term and later in life. In the near term this person will burn out. Later in life they will regret not having a family and a life when they were young and healthy. And for what? To write code that 5 years from now will just rot unused in some Git repo. This level of effort is only justified in one case (and maybe not even then): if you have significant traction building your own company. If you're working for someone else, your imperative ought to be to extract maximum pay for minimal work, to the extent that is long-term sustainable. Burnout takes years to recover from. Some people don't recover at all and leave the industry entirely. I've been through burnout myself due to similar stupidity when I was younger, and I strongly regret not pacing myself - the effects linger to this day, a full decade later. I am now unable to "code for fun" for example. Worse, I was married at the time (still am), and neglected my wife and kid to build my "career". Not worth it at all.