Rather than arguing that someone ought to get organised, ask one question. Would your life be better if fewer things slipped, fewer people were annoyed with you, and you spent less of the day worrying about what you had forgotten?

A system survives if it gives back more than it costs. Every time your diary saves you a phone call or a scramble, you have bought yourself a little more willingness to open it tomorrow.

Think of a calendar as memory kept outside your head rather than as a test of discipline. Its whole job is to answer what you should be doing now, so that you do not have to work it out.

A calendar that catches only some of your commitments is more dangerous than no calendar at all. You look at Thursday, see a clear afternoon, say yes, and only later meet the thing that never got written down.