I've never had a lot of luck with categorizing and allocating either. Which is actually fine, because what category (or, God help us, categorIES) a task fits into is ultimately not a terribly valuable piece of information. It's costly to obtain, in terms of time spent categorizing, but yields no particular insights, other than maybe the frustrating realization that a surprising number of tasks fit plausibly into multiple categories. (Which is as it should be, if you're productive and your life is reasonably well integrated.)
The only question your system needs to answer is what to do NEXT. And the only categories as far as I'm concerned are "work" and "home." Keep it simple. Therefore I have a spreadsheet for each. Within each one, here's what I have:
I have a list of things that repeat every day, called "dailies." I do those first.
Then I have a list of small one-off tasks that can be taken care of relatively quickly. This list is called, inspiringly enough, "uncategorized." I do these right after the dailies.
"Uncategorized" is also the default landing place for any new task. Sometimes you just want to write something down without thinking about it much. Next time I go through the list, any tasks that need to be moved to another list, I'll do it then.
Finally there's the "projects" list, which consists of bigger tasks with sub-tasks under them, in order, and with deadlines noted, and the whole bit.
Using macros, key bindings and event triggers I can re-order all these lists with one keystroke. Each item has an integer next to it for sorting. I usually use 0 through 4:
0 - waiting for something or someone else
1 - doing right now
2 - next
3 - later
4 - tomorrow
You'll notice that by doing "dailies" and "uncategorized" first, I'm doiog the opposite of what some advice suggests: I sweat the small stuff first. That's because I'm a night person, so I save the morning hours, when my mind is dull, for small, routine and easy things. By the time I get to my projects list, I'm fully alert and ready for it.
But if you're not a night person you could certainly do projects first, then one-offs, then dailies, or something. Also there's nothing stopping me from putting something demanding (that happens to be repetitive) on the "dailies" list for example. Something like studying a new technology for a couple hours a day would go on there. But I would probably tend to postpone it until the evening, i.e. put it in the "dailies" portion of the "home" spreadsheet, and start it when I get home from work. (Or if I'm working at home, start it when I declare that I'm home from work.)
By the way (back to "projects"), I try like hell to have only one project active at one time. Unless fucked-with by someone else, I will endeavor to finish each one that I start, before moving on. There are many reasons why focusing resources on fewer projects sequentially (rather than more projects simultaneously) is the best way to do things.
Therefore my day consists of, go to work, get a bunch of small ducks in a row, focus on a project for the mid-morning and afternoon, go home, do daily chores or studying, get small home-ducks in a row (things like "order underwear" or whatnot), and if there's time (usually not until the weekend) work on a home-project. I like sleep.
Things that recur at intervals other than a day, those go in the calendar, and I get a reminder, every n months or n weeks or whatever. From there I use automation to transfer it into the "uncategorized" area. (Home or work, depending on whether it came from my home or work calendar.)
If I ever think up a big over-arching life goal, I will make it a project or split it up into projects. Projects are things that you do. Goals are things you just think about, that I don't really believe in. Or rather, if it's important enough as a goal, I don't need to write it down, I just let it influence all my decisions in that direction. It's best not to have too many goals; just a few high-quality ones. Kind of like how it's best to have just a few high-quality friends. Life is not a shopping expedition; or actually maybe it is, but I say that as someone who thinks the fewer things you "buy" (into), the better. Also it's not good to try to plan out your entire life; give yourself some freedom to steer the ship in real time. Rely a little on your wits and creativity instead of on a script.