The more you divide your time, the less efficient / productive you will become.
If you spend 10 hours a week on each of 4 projects, in 4 weeks you will have done a weeks worth of work on each, right? Wrong. In fact, you’d probably be lucky to get half that. The more you divide yourself, the less you’re going to get done on each thing, just because of a lack of focus and a need to keep context-switching.
I must be weird because I find the exact opposite works for me: the more things I have going on at once, the more I get accomplished. Which was a real drag last summer, when I was trying to single-mindedly learn Cocoa programming and get Musicality out the door, and I was all like "ooh, shiny" at all the cool technology and new APIs I was discovering. I did everything I could to block out distractions and Just Get It Done and I think it ended up doing more harm than good. Since then, I've started easing off and gradually taking on more and more threads with, as it turns out, no loss in progress on any individual one.
Partly I think this is a brain fade problem. When I'm looking at the same thing for four or six or ten hours I just stop seeing it. Maybe it is the same brain mechanics that tunes out a background noise.
Partly it's a motivation thing. If I know I've got all day to work on something, I don't feel the same urgency as when the timer is counting down. I can…and how do I say this…if I only allow myself two hours a day on a project, I will get done almost the same amount as if I gave myself all day. When I sit down to it, I'm motivated and my brain is engaged. I've had a whole day for my brain to chew on the problem and so I've got two or three things I'm ready to do right off the bat. But once those things are done, once I find myself problem solving, my output falls way off. It is time to move on to something else and let me poor brain think about the next steps for a while.
I've talked about this before, but I think I (and maybe we, but I won't speak for everyone) do our most effective problem solving away from the desk, giving inspiration a chance to appear. I can't recall the last time I ever had an "a-ha" moment while doing the work. So you can almost think of this approach as twenty hours of finding a solution, and two hours of writing it down.
I say "two hours" because I've found that to be about the ideal amount of time for me to stick with one particular effort. Then I take a short break and switch gears to something else; the change of context gets my brain engaged again. But I've found for many things a shorter timeframe works even better. For instance, I want to get writing again. Writing, and particularly blogging, seems to be one of those things that you can only get better at with practice, but the only way to practice is to do it. So I've been writing for 15 minutes each morning, off-site. The tight time frame is really motivating and forces me to get to the point. And it is short enough that I don't feel like the "more important" projects are getting shortchanged.
Interesting: I initially didn't feel like I had time for writing in the morning; my routine was already too full. But once I made the decision to do it, and stuck with it, the time appeared as if out of thin air. I, almost unconsciously, got just a little more efficient with everything else; that slight sense of urgency was all I needed to get more done.
Now Premake gets 30 minutes in the afternoon, assuming I'm not entirely brain dead from my day job. Musicality gets one hour every morning, even on the weekends. The day job gets the bulk of my day—c'est la vie—but even there I try to switch between different bits of the work.
I've found this works best on a fixed schedule. If I allow it to "float" my mind will start to rationalize slacking off by assuming that I can just add another 15 or 20 minutes. And best if I repeat it every day, so I can act on whatever insight I come up away from the desk in a reasonable amount of time. And because you get used to it, used to the pattern and the rhythm, and your mind begins to almost naturally flow from one gear to the next. It's a cool feeling when you really get into it.
Always ambitious, I'm currently trying to find a way to add two more blocks to my day somehow. One to get a new small commercial project a la Musicality started (the saying about eggs and multiple baskets); another to restart a pet project that I've no idea what to do with, but can't resist working on. And then I've a friend who insists we start playing music again, so that'll be another. But that's what we're here for right? To experience life, to live it. To do and be and have fun with the lot of it.