Is it true that PhD students need to work 10-12 hours a day every day to be productive?

The answer is no.

There are a lot of factors in play. With my work, a lot of it is creative so it is hard to say when I am working or not.

Do people expect students to work that many hours? Maybe, but it isn't healthy (and maybe not legal).

Do people really work the entire time they are at work? Probably not. Your productivity certainly goes down the longer you work. Whether people goof around or not isn't specific to Academia and can happen anywhere (I don't find goofing around to be a negative thing).

I too have read several studies about the limited number of hours that people have for mentally demanding tasks. In fact, I read a study about programmers that said they were lucky to get 1-2 hours of solid work done in a day. This info can help you organize your day so that you work on difficult tasks in the morning and then mechanical tasks in the afternoon. Also, studies have shown that taking breaks and going on walks can help improve your productivity.

There isn't a cookie cutter answer for everyone. It depends on yourself, the type of work, your advisor, and your coworkers.

Most people who brag about how many hours they work are inefficient. Because they are inefficient, they feel a need to point out how many hours they work - rather than pointing to the quality of work. Keep this in mind.

Some PhD programs will allow you to be more isolated from non-PhD related work than others. If you have to teach, for example, that might take a considerable portion of your week - preparation, class, grading, etc. This might cause you to have to work many more hours if you want to make progress on your dissertation than someone who does not have to teach.

If you are unlucky and have your "paid research" different than your dissertation research the same thing can happen - you have to split your time into different buckets. The quality of your advisor and their expectations thus has a big effect here, too.

How quickly you want to graduate can affect this too.

That being said, how you work affects how efficient you are.

• Quality of your working hours
  • Sitting at a desk for 12 hours straight is most often bad.
  • Working 12 hours, taking 10 minute exercise breaks every hour? Much less bad.
• How deliberately you work
  • Do you sit aimlessly without tasks?
  • Do you have a system to keep track of what you need to do?
  • Do you manage your energy (doing high energy tasks when you have energy, low energy when you don't) or do you just blindly do tasks?
• Do you know when to call it quits -- or keep going?
  • If you have a high energy task you are doing great at, do you keep that momentum going?
  • Conversely if you feel burned out, do you just take a break? Or keep going anyways?
• When do you work?
  • Some people rock 5am-7am. Some people rock 1am-3am. Some people are afternoon people (my prime time is about 4-6pm - I can accomplish insane amounts in this time compared to the rest of the day). Figure out when your times are.
• Do you have distractions?
  • An hour with no distractions during writing might be better than 4 with continuous interruptions.
• Read this article and apply it ruthlessly to your life. You are a maker, your advisor is probably a manager.

You will likely find that the better you work, the less you have to work. But simultaneously realize the more you could work (so if your goal is more X then it's great).

The how, when, and what for when we work dramatically affects our ability to work tons but also whether or not we have to.

My experiences suggest the answer is: possibly. Or perhaps more accurately sometimes.

A lot depends on the field you're in. I studied for a PhD in life science, where a lot of time at the lab bench was required. This is skilled work, but it's not "creative" nor does it involve much mental effort. So it's certainly possible to be productive at it for longer than four hour stretches.

In addition I often had to go in at the weekends to observe the results of my experiments. Cells don't grow to a useful 9-5 weekday schedule, unfortunately! I imagine other areas of science will impose similar time pressures.

I treated my PhD as though it were a job. Although I did work longer than 8 hours a day and I did work weekends when necessary, I viewed this as an annoying imposition and tried to minimize it. Other students and postdocs in the lab did longer hours and were more productive.

When it came time to write up my thesis, I discovred I simply did not have enough material to make it worthwhile. Ultimately I was forced to apply for a lesser research degree (an MPhil) and when it came to the crunch, I was not even able to obtain that with the evidence I'd gathered. Part of this is unquestionably down to lack of bench-hours.

I cannot speak about non-practical subjects, but even there I would imagine the amount of reading, learning and documentary research required would be significant, and would not involve creative mental effort. But my experience suggests that while ten hours a day, seven days a week is likely excessive, a successful research degree does involve time and effort well beyond that required for a regular highly-skilled job.