I’ve always liked doing things, and checking them off a to-do list. Over the years, I’ve tried different lengths, and have surveyed a few friends, family members, colleagues and passers-by. Here are the evidence-based results, statistically significant to three decimal places, where n=20 or so.

1.      One is a good number to keep a handle on. Most of us can do one thing every day. The trouble is, that if you fail to do it, you would feel like a real loser, someone who, when they give themselves just one thing, can’t even to that. Not a good number for folk with already poor self-esteem. Better to have 100 errands to run and complete half of them.

2.      Binary works well, especially for IT types.

3.      Three is good for those literate in rhetoric.

4.      Four it okay, for keeping activities front-of-mind.

5.      Five is a handful, which is a useful mnemonic.

6.      Half a dozen works for pre-decimal nostalgics.

7.      Seven is a magnificent number.

8.      Eight is a lucky number.

9.      Nine is for under-achievers who need to feel like they’ve achieved something, or for over‑achievers who believe that their nine is equal to other people’s ten.

10.  Ten is conventional, boring, and makes people feel manipulated by an imaginary manual.

11.  If you have eleven items on your daily to-do list, you’re well on your way to Chapter Eleven, to believing that 11 is 10+GST, or to being more alpha than competitors with ten to-do list items.

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