It depends. When I'm in the zone I work myself into the ground. When I'm out of the zone I'm very unproductive. I found a secret that helps me get into the zone though. Its a secret, for $9.95 you can order my e-book or just read the rest of this comment.
I'm not a planner personality at all and I find planning my time does no good. However I do respond to accountability. So what I do is make a table with the X axis representing the days of the week and the Y axis representing each hour slot in the waking day. I print this out so I can carry it with me and one sheet of paper has one week.
I then fill in the table throughout the week with what I did during that hour. If I ate, I put down that I ate. If I was asleep I put that down. If I wasted the hour I put down an X. If I did something productive I write that down. This method works for me and after two weeks of this I'm back in the zone and don't need to track my time anymore.
I don't track my time at all any more. I have found that it's useless. I used to spend 8 hours at my terminal and thought I had a good day. Until I realized that I got so little done.
Here's what I do...
I DO NOT log on without a written plan for the session. I start on the first thing on the list and work my way down. Most lists only have one or two things to do. I almost always get done whatever is on the list.
I usually make the list the night before while reviewing that day's code. Sometimes I do the list very early in the morning. It's amazing how full my mind sometimes is when first waking up.
It's NOT how much time you spend. It's how much you get done. I'd rather work 20 hours to accomplish x than 40. (Better yet, work 40 to accomplish 2x).
You're probably more of a planner personality then. I think some may have missed my point. When I write down what I did--I don't say I sat at a terminal and count that as productive. I make an honest assessment as to whether I made progress or not.
This keeping honest puts myself into the right frame of mind to stay productive. It builds momentum. I feel a small sense of accomplishment every time I log a successful hour and it encourages me to want to keep doing it.
I would count anything useful towards whatever my goals are as productive. Working in a notebook planning higher level things, developing an algorithm, or sitting down and writing code are all part of this process.
I don't think my productivity/working hour is being questioned here so I won't address that.
Two weeks and you're back in the zone? How long does it stick? For me, it fluctuates much more rapidly. Most days I'm in the zone for solid chunks of time and not in the zone for some chunks as well. Occasionally I'll have a bad day or two back to back. However one day rarely carries over to the next in terms of productivity.
Until I've gotten where I need to get to. I used to use this technique when I was an undergraduate to get through tough periods of the semester.
Recently, I used it on my startup after I finished grad school. I had a goal of getting a beta out and pushed myself into this working mode. I then kept going until I released the beta.
I tend to spend months in a zone where I'm able to concentrate and think about a project. During this time my social drive is down. Then I spend months in a zone where I just want to be around people and I can barely work. I think this technique is a way to throw myself into the working part of my brain at will. I won't claim to understand it. And I won't guarantee it will work for you. I just know all the plan things out stuff I was taught did me no good. This worked and so that is why I point it out here.
I work out and eat well but any one who knows me will tell you that I am life balance FAIL.
I'm not a planner personality at all and I find planning my time does no good. However I do respond to accountability. So what I do is make a table with the X axis representing the days of the week and the Y axis representing each hour slot in the waking day. I print this out so I can carry it with me and one sheet of paper has one week.
I then fill in the table throughout the week with what I did during that hour. If I ate, I put down that I ate. If I was asleep I put that down. If I wasted the hour I put down an X. If I did something productive I write that down. This method works for me and after two weeks of this I'm back in the zone and don't need to track my time anymore.