I did Pomodoros all the time before I really started programming. Now I just like to lock into a flow and work until I can't or I get frustrated debugging and take a break
On a somewhat related note, I've noticed that I only really smoke (tobacco) at work, and rarely at home. I'll have 6-8 throughout my 10 hour workday and maybe 1 or 2 after I get home... I guess my job really is killing me haha.
I do set a timer on my watch when I am taking a break (grabbing coffee / checking HN), but that's kind of the opposite of P.