There are many times when if one has trail mix, water and caffeine on hand one can keep working for hours on end with only quick pit stops.
And then there are moments one needs the skill of catching… when the brushwork is getting too frantic, when you’re starting to get lazy about mixing new colors because you just want to press through, when the cuts are getting sloppy… or in the case of last night the blade on the dremel is starting to get out of your hands. Tired, frustrated, too much adrenaline, not enough food or sleep, or just sensory overload. You have to learn to step outside yourself and STOP. Sometimes some deep breaths, a meal break or similar will give you a few more hours after that. Sometimes you can ride the ragged edge and put the frenzied energy to work (though not with power tools I think, but a frenzied expressionist piece? Absolutely).
Last night I quit cold-working the glass face an hour early. Glass, power tools and sleep deprivation are not a good mix. What’s more the intense energy of creation tends to drive one to work faster in such a moment, to push harder just to get through things. That is the moment to catch oneself. Thankfully I did and went home. Otherwise I’m fairly sure I would have caused either my piece or myself harm in that last hour. As it is we are both fine.
Stopping at the right point not just for the work, but for oneself is one of the essential skills of an artist. It’s not something that gets addressed by many teachers, but I doubt you’d find many successful artists who lack it.