alderi've honestly never gone over 24 hours, dunno how people do it
i pass out after being up for 18~ish
That's the biggest hurdle! Usually somewhere between 18 and 22 hours for me, but after that it's like the longer you stay awake, the more awake you will feel.
I've never gone past 49 hours, because the edge of staying up that long starts to be more of a cost than a benefit. But I do go past 24, into the 30-40 hrs territory pretty often (once every three weeks on average?) Yesterday I was awake for 37 hours.
Something I think is really important to consider/understand on this topic is that you shouldn't do this if you don't want to be awake really bad in the moment. Staying awake past 20 hours can be god fucking awful when you don't want to do it. However, the more fucking amped to be awake and do shit you are, the better the experience is. You flip the duality on it's head, being in control of your body, rather than it being in control of you. This is why most people who don't enjoy it are people doing it for challenge or insomniacs.
I don't know if it has to do with like your body kicking into a heightened sense of awareness or some fight/flight shit, but I love staying awake for a really long time, especially when you got something you're psyched to be working on or do during that time. Frequently, I feel way more awake, more human, more ALIVE, in those days than I ever do in a normal one. Also, I often make progress on chains of thoughts simply due to how long I've been in awake. When you wipe the fucking slate every 16 hours and have to reorient yourself every morning, it can be limiting in a way. Ever make some huge revelation, think really hard about something, or write a big essay about some important topic, then go to bed, wake up, and the mindstate you were in the night before has slipped away? This is the only way to avoid this. Granted you are mentally active, 40 hours awake can give you a lot more time within the same general thinking session to connect ideas and add new layers to pyramids of associated thought. I could go on forever about this, thx for making thread.