This is interesting actually. I remember a time I stayed up all night trying to get a script for a game working (hobby project). I was hacking away all night until early morning and I just couldn't fix the issues. After a good sleep, I'd fixed the issue and got it working as it should within an hour. The lesson for me was that I shouldn't put my health on the line for these types of things; it doesn't help in actually making progress and it could set my performance back weeks.

Another big lesson, which is more general and took a few more mistakes, was the value of stepping away from a problem after intense conscious focus on it. This may or may not mean sleep on it but just means taking your mind off it and let the back of your head tick away on it. I think this might actually be the source of "eureka" moments too, which means flashes of ingenuity are not exactly what they seem!