Don’t really understand the deniers here. I’ve also worked through weeks of literally waking up and building software until time to go to bed, 7 days a week. It is definitely possible, but it destroys you mentally. It was never the expectation that it would be the norm, so my wife was supportive.
For him work constitutes for the most part just being at the bodega. I worked from home for about 5 years. I was at home nearly all the time, and did concentrated work 8-9 hours a day. Can I claim I actually worked 16 hours a day just because I was at home and there were deep learning training runs running in my garage? Of course not. When I say "work" I specifically mean _doing_ something, not just being there.
My father works partly 18h a day for several weeks only with breaks for fast eating and 3h sleeping. It's not like that he enjoys it much. But as a self-employed you have to work that much if you want to keep your customers (delivery date is in the quote, so you have to deliver).
He has done that for the last 40 years haha since I know him never had been different.