Work projects: typically on the order of a dozen
House projects: Probably over 20 distinct chores over the course of a week, plus currently two maintenance things that I can't do myself and have to call people repeatedly because 90% of contractors just don't show up unless you remind them to.
Kids: most things can be handled immediately (e.g. sign a form), but there are always at least half-a-dozen things in the air that can't for one reason or another.
Other: Resubmitting medical bills to insurance (can only be done during business hours, I typically open my mail after business hours). Contacting bank about something. &c.
Here's a fraction of what I'm doing today, including one from each category (except calling a contractor because my wife is doing that):
- I have to contact my bank during business hours because they sent me the wrong form (discovered while I was filling it out this weekend).
- I need to call a coworker because one project is blocked on them regarding an issue that they haven't replied to my e-mail sent Thursday afternoon.
- I need to pickup my daughter from a day-camp on the way home from work. Before dark, I need to weed part of the front yard.
- Tonight the trash (but not the recycling) goes out to the curb for a pickup tomorrow morning.
Yes, I have met people who can keep track of these things in their head. I am not one of them.
I think you can find the answer to this question by looking at the comment thread of any TODO/notes/task-tracking submission on HN.
I'm more curious about a broader question: at what point does life complexity actually require a formal system versus just mental tracking? Tech people are, for the most part, the only people I encounter actively using and iterating on their TODO solutions, and I am skeptical that in general they lead more complex lives.
The need to update a piece of software doesn't give me any physical cues, and if I have a couple dozen tasks like that waiting on me, I'm never going to remember them all unless they're all popping into my head throughout the day. That pretty much is how I used to try to do it, and it wasn't good.
I have to wonder if some people use these systems to make themselves feel more important than they actually are.