There was a time when the blood was younger, meals got made by elves (or perhaps grandma), house took care of itself (or by my dad) and all I did was work during deadline times of Dec-Jan-Feb. During such times, I would brush my teeth as soon as I woke up at 6.30 AM, fresh as a daisy, drink coffee handed to me by dad, and went up to my office room, to work continuously until grandma called me for various meals, until late night (and by that I mean 10 PM), when dad gave me a glass of warm sweet milk to end my busy day. The net wasn’t as fast as it is now, neither was there so much information available online and while I waited forever for the dial-up modem to connect and search for stuff, I’d scour books and journals, rack my brains with the scientific principles behind a bunch of ideas I was supposed to write up, and at the end of the day, hit the sack and be out like a light.
Now the net is infinitely faster. Any information I need (beyond Rule 34 that is) is available before I even finish the question. I have had 17 years of doing this, which hopefully makes my brain faster with ideas. Yet, my limit of continuous work is only 6 hours it seems. With all breaks thrown in. At the end of six hours, my brain feels fried to a crisp, I get a migraine, and every bit of my body hurts like I ran a marathon, while all I did was sit with my laptop. The skin over my thighs are raw. My eyes are sore. My fingers ache. Every joint creaks when I get up. And when I go to bed at night, I get Kafka dreams of biopolymer and nano cellulose and graphene and algal ethanol and composites and what not.
Age is a dog, I tell you.
How long can you work continuously before your body and mind break down?