Ideally, I have 2-4 projects to work on at any given time. 1 is too few; I get bored quickly and it's easy to find something else to do. 5 is too many; I'm paralyzed by the fear of not getting everything done on time.
Having 2-4 projects on my plate (generally 2 tough things, 3 medium-level things, or 4 easy things) is perfect.
Since high school, I have worked under a model that I call Purposeful Procrastination. It works as follows:
- Work on Item #1 until you get distracted, whether from boredom, disinterest, exhaustion, or priority switching
- Procrastinate on Item #1 by working on Item #2
- Work on Item #2 until you get distracted, whether from boredom, disinterest, exhaustion, or priority switching
- Procrastinate on Item #2 by working on Item #1 or Item #3
- ...and so on.
I have found that, in the end, I get everything done - not only on time, but also under budget and under minimal stress. I don't play online games or read celebrity gossip (unless I'm stuck with only 1 project or more than 4 projects, in which case my brain can't focus appropriately). In the end, productivity is up and I actually spend less time in the office. Less time in the office means more time to work out, to spend with the family, and to do non-work-related things.