Do any programmers actually work only 8 hours a day..? I've never seen evidence suggesting this is actually true. 10+2 seems more realistic.

I've worked as a programmer for over 30 years.

I've had two really productive periods during that time.

One of those periods I spent about 4 hours a day coding, totally focused - get to work at about 5:30 after a leisurely brunch and a 30 minute bus ride during which I planned my coding for the day, jump on a machine and pound the teletype for 4 hours or so, and go home, nearly exhausted. This was writing device driver assembler routines and image processing code.

The second period, I was implementing a prototype of a distributed OS, about 10% of a 3 inch thick spec which defined the whole thing down to the level of small procedures, with a hard 6 month deadline (which was what I had estimated the job would take). I worked steadily for that 6 months on a 40 hour schedule, and finished about two weeks before the demo was given.

I'm currently reading On Lisp and The Four-Gated City (by Doris Lessing), for whatever that's worth.

Personally, I'm worthless after 6 hours of programming.

I'm decent for most of those six hours, and I can churn out maybe 3000 lines a month, but I tend to need a holiday afterwards.

I just quit my cubicle job to switch to iPhone programming, and it's been interesting how hard it is to knuckle down and really get started.

Some don't even make it to 40hrs a week, ask DHH and crew: http://www.37signals.com/svn/posts/893-workplace-experiments

I sit at a terminal for more than 8 hours a day, but I do things other than program.

There are times when I have done productive work for 20 hours straight, but most of the time I do about 4-6 hours of work.