It is possible within all humans with the spice melange....
However barring becoming a mentat I've noticed this variation within myself as well and I've noticed the times I am able to go and go and go is when I have a lot of momentum. It seems that doing things that require will naturally result in more will so it isn't that the task is easier but rather my ability to overcome is increased and it is a smaller % of my overall energy expenditure to do.
In accord with this I've noticed that for me taking a "break" is when I get far less done and it becomes much harder to do anything.
I've also seen that when I have things booked back to back to back no matter the density it seems I can keep going so long as I don't stop to think about how tired I am and just keep going. It's when I get breathing room that it seems like everything I've already been doing is impossible.
The other big help for me was Adderall, I have ADHD bad so if I am not working under pressure and a deadline sufficient to release adrenaline I can't do anything. That was until I got my medicine then I finally felt like I could be who I could be without being a nurveous burned out wreck all the time.
I also found that I work pretty well when under pressure or someone request something challenging (especially if it's a girl I like :D). However, both are external forces and they don't come very often. It's VERY difficult to find jobs that consistently provide enough challenge because those jobs are very picky about candidates. Neither often there is any request coming from other people.
However barring becoming a mentat I've noticed this variation within myself as well and I've noticed the times I am able to go and go and go is when I have a lot of momentum. It seems that doing things that require will naturally result in more will so it isn't that the task is easier but rather my ability to overcome is increased and it is a smaller % of my overall energy expenditure to do.
In accord with this I've noticed that for me taking a "break" is when I get far less done and it becomes much harder to do anything.
I've also seen that when I have things booked back to back to back no matter the density it seems I can keep going so long as I don't stop to think about how tired I am and just keep going. It's when I get breathing room that it seems like everything I've already been doing is impossible.
The other big help for me was Adderall, I have ADHD bad so if I am not working under pressure and a deadline sufficient to release adrenaline I can't do anything. That was until I got my medicine then I finally felt like I could be who I could be without being a nurveous burned out wreck all the time.
That's just my perspective with n=1.