[the_cramer]

Software developer here. I work about 6 hours concentrated on stuff before i notice a drop in cognitive abilities. That's not counting the short breaks for toilet, getting coffee etc... Then it's roundabout 5-5:20 hours. These breaks normally don't get me off the topic very much as i can continue thinking about what to do next or crunching on a solution.

But after that time I start to mix things up and make mistakes. So I really wish 6 hours were the actual work time... but in reality I have to work 8 hours a day.

[evrimfeyyaz]

I think you meant "6 hours... counting the short breaks." In any case, I think six hours is a good number.

So, you have to put in eight hours of actual work? A usual workday is eight hours, but I'd say most employees probably do less than four hours of actual work every day.

Are you a freelancer or an employee, if you don't mind my asking?

[the_cramer]

You are correct. 6 hours including the breaks.

I am an employee at a large distribution company for IT hard and software. I think there are many factors that play into how long a productive day really is:

Type of work - is your job requiring brainwork all the time or maybe you have some work in-between that just requires execution prime to thinking work?

Environment - how good are you shielded from distractions?

Communication - do you really need to be shielded? Maybe you need a steady communication to proceed with your work. I'm thinking about the guys at stock market e.g.

Type of breaks - This is a big one and up to personal preference to a degree. Are you forced to take a break? Is it a hard force or a soft force (telephone vs. mail). Do you have to respond immediately? A big problem for me e.g. is interruptions when i'm in the middle of it. It takes a fair amount of time to get back into the zone.

If this happens i often like to refer to this article: http://blog.ninlabs.com/2013/01/programmer-interrupted/ It's hard for people to understand why interruptions can be very harmful for work.

So if i say 6 hours, this is the maximum for me to work concentrated on one topic. Interruptions diminish this number, shorten my concentration timespan and often make the day not as productive (subjectively).

edit: formatting

[evrimfeyyaz]

I agree, this method probably works for a "maker" and not a "manager" (or a person whose job requires them to move between tasks a lot).