[spiralhead]

My 2 cents. I am not "experienced" in that I haven't yet achieved my millions, but experience has told me "forcing" myself to continue hacking away when I'm clearly experiencing physical fatigue only leads to more lost productivity down the road.

For example, forcing myself to continue working at my computer when I don't feel like it will lead to eye strain, back pain and anxiety. I will often wake up with a headache after such marathons. I refer to this as burnout. Burnout is very real.

In my early years of programming I could work non-stop because I was doing something new almost every day. And for someone that likes new experiences, it was exciting. But after years of experience, programming in-and-of itself feels more and more like labour.

Don't get me wrong. I still love programming, in general. I've just become more focused on the end-results of programming--of what it makes possible, what it does for people. The act of programming itself, while being something that will always be a significant part of what defines "what I do", is no longer something that can sustain my interest full time.