Seven years ago I started keeping a decision journal. Not a regular journal — a journal of the specific moments I made a decision that mattered, recorded before I knew how it would turn out. It is, by a considerable margin, the most useful thing I've kept.
The template
The decision, in one sentence.
What I believe will happen if I do it.
What I believe will happen if I don't.
What I'd need to be wrong about to regret the choice.
The single biggest thing I'm uncertain about.
Five lines. I write them in three minutes. The discipline isn't the writing — it's writing it before the result is known.
Why this matters
Memory is generous to past you. Without a journal, your brain quietly rewrites every decision to look like you knew it would work out. You lose the ability to calibrate. The journal is a forensic tool against your own narrative.
The rule I broke, once
There's one rule I'd put above the others: don't read old entries while making a new decision. They will pull you. The journal is for after, not during. I broke this rule once, on a job offer in 2022. I let an old entry about turning down a similar role color the new decision. The two situations weren't comparable. The decision was worse for it.
Decision journals are a long game. Yours will be most useful in year five. Start year five now.