SRE maturity is not 'do we have an on-call rotation', but how deeply the discipline is wired into the product. A 5-step ladder: Reactive → Managed → Proactive → Resilient → Antifragile.
Three things change at each level: what we measure (uptime → SLO → user journey SLO → business SLI), how we respond (heroics → runbooks → automation → self-healing) and how we learn (firefighting → postmortems → game-days → chaos in prod).
The ladder helps a team honestly name its current step and pick 2-3 practices to install to move up — without a cargo cult of 'let's do it like Google'.
Name the current maturity level without trying to look better than reality.
Compare what the team measures, how it responds, and how it learns after incidents.
Choose 2-3 practices that move the team to the next level.