Documentation Decay Half-Life

Documentation Decay Half-Life is the interval between a process changing and the wiki page describing it going wrong. Every agency process has one: a client onboarding checklist, a QA rubric, a reporting template. The half-life shortens as delivery velocity rises, so a retainer running weekly campaign iterations decays faster than a quarterly strategy engagement. The framework matters because stale docs do not fail loudly; they fail as rework, repeated questions, and inconsistent client delivery when a new hire follows a page nobody has touched in eight months. Slite attacks this by monitoring Slack, GitHub, and Linear for drift and drafting fixes for human review, while GitBook runs a stale-content agent and Guru auto-verifies pages as usage increases. The practical move is to measure half-life per document class, then assign review cadence by decay rate rather than by calendar. A 30-day half-life page needs an owner and a trigger; a 12-month page needs almost nothing.