It is much easier to try one’s hand at many things than to concentrate one’s powers on one thing. (Quintilian)

The tasks one is faced with in work can be broadly divided into two categories:

  1. “high-intensity” tasks, which are complex and require your full concentration and focus (e.g. writing a research paper; preparing for a class or talk; writing a lengthy, detailed, and careful email; thinking about a mathematical problem; reading a research paper or text), and
  2. “low-intensity” tasks, which are routine (but can be time-consuming) and do not require much mental energy (e.g. filling out paperwork; teaching a class or giving a talk that you have already prepared; writing a short email response; errands and appointments; reading email or browsing the web).

Working with high-intensity requires a rather different “mode” of thought than with low-intensity tasks.  (For instance, I find it can take a good half-hour or so of uninterrupted thinking before I am fully focused on a maths problem, with all the relevant background at my fingertips.) To reduce the mental fatigue of transitioning from one “mode” to another, I find it useful to batch similar low-intensity tasks together, and to separate them in time (or space) from the high-intensity ones.

For example, you can devote a block of time to clearing a lot of “trivial” tasks off of your plate.  Schedule all the “distracting” tasks (e.g. office hours and other appointments) in a single day; try to bunch up teaching days; etc.  (I found, for instance, that teaching two sections of a large calculus class back to back (e.g. at 9am and then at 10am) led to significant time savings in class preparation (as well as savings in mental energy), when compared to teaching two different classes, or the same class at very different times.)

One can also do this blocking off in space as well as in time.  For instance, with regards to keeping track of paperwork, I have one small area of my office for “important” forms and records that I am likely to need to deal with again in the future, and a larger area in another part of my office for “mundane” paperwork which have a low (but non-zero) probability of being needed again in the future.  I don’t organise or file the latter set of papers very much, given how rarely I need to retrieve files from it; it tends to accumulate in a pile, which I sort through (and mostly discard) every few months or so.  (But I do make an effort to keep the “important” forms relatively organised, and to not have them be cluttered by the much larger set of “mundane” forms.)

In a somewhat analogous fashion, one can have an “out” tray for low-priority physical mail, and send them all out at once, rather than making multiple trips to the office mail room in one day.  (While doing so, of course, that would be a good time to check one’s mailbox, or any other task that requires walking around the department.)

With regards to email, an assembly line approach seems to be efficient: wait until it builds up, and then (a) pass through deleting spam, (b) pass through again dealing with easily dealt with emails (ones that need to be read once and discarded or filed, or require a very brief response, or pushed into some sort of “pending” folder; and then (c) deal with one or more of the emails that demand a longer response, if you feel that this is an appropriate time to do so.

If you like to browse multiple web sites during the course of the day, I recommend using a feed aggregator (I myself use Google Reader) so that you can do all your browsing at once, so that they do not distract you from your other tasks.

If one has a batch of tasks that are both low-intensity and low-priority, then it is probably a good idea to set it aside until one really needs a break from more high-intensity work; for instance, if I get too frustrated on an obstacle in my research, I find this to be a good time to go do some accumulated errands or paperwork, or even just to catch up on my email and web browsing.  Having some easy tasks of this nature lying around is then handy for killing time in a reasonably productive fashion until one’s creative energies return.

Note that batching only works well for low-intensity tasks.  A high-intensity task requires so much focus, and exhausts so much of one’s mental stamina, that it can be counterproductive or distracting to mix this activity with other low or high intensity tasks.