James Kwak's excellent post The Myth of Efficiency is rooted in the idea that for most professionals "the length of their workday isn’t set by a clock, but by their sense of when they’ve done enough for the day."
I’ve become very skeptical of the simple argument for efficiency studies….The idea is that time has a monetary value (say, the per-hour employment costs of each employee), and if you save time, you save money. One example that LeBlanc mentions is moving printers. It seems to make sense on its face. You spend time walking to and from the printer. Therefore, printers should be located to minimize the total time people spend in transit, which could mean moving the printer closer to the heavy users of printing. Then those people can spend more time at their desks being productive.
But there is a serious fallacy in this argument: the assumption that the constraint on productivity is time at your desk. Let’s leave aside the issue of whether you are productive walking to the printer. The more serious issue is that you aren’t equally productive the whole time you sit at your desk. What if you spend your extra two minutes (in reduced time picking up printouts) at I Can Has Cheezburger?
In other words, doing X may save you time, but that doesn't necessarily mean you'll then fill that time with productive work. This seems simple but many efficiency-obsessed people forget it.
Here are few random, current thoughts on the topic:
1. Each morning I write down the 4-5 things I want to accomplish in the day. I try to make it realistic. The idea is to define "done." Otherwise, I will always feel like there's more work I should do before going to bed. Here's a related HBS post titled An 18 Minute Plan to Managing Your Day.
2. My guess is even talented and productive people can do only a few hours of hard, real focus work per day and a few more hours of medium-focus per day. The rest is time wasting.
3. I use Toggl to track my time. It's excellent. I turn on the virtual stopwatch when I work on certain projects and turn off the moment I do something else, so I get an accurate look at how much time I'm investing in certain projects. It also puts me in a state of mind: when the stopwatch goes on, email goes off, and so does random web browsing. Eventually, perhaps I can be like Jim Collins and carry around a real stopwatch with me. Toli Galanis uses this stopwatch.
4. I get little to no value out of RescueTime.