What is the right rollout roadmap for engineering maturity?

Phase the work by risk, not by technology fashion:

• P0 — protect now: secret scanning, role/tenant authorization, financial invariants, backups, admin MFA, blocking CI. *Exit:* no known exploitable P0, and critical data can be restored
• P1 — stabilise: metrics and traces, query audit, connection pool, rate limits, bounded retries, private files. *Exit:* critical SLOs measured and runbooks work
• P2 — verify scale: k6 workload models, CDN/cache, index fixes, controlled autoscaling, quota plan. *Exit:* peak target sustained with margin and measured cost
• P3 — specialise: workers/outbox, search index, replicas, partitioning if required. *Exit:* bottleneck-specific benchmarks show value
• P4 — platform expansion: Kubernetes, microservices, sharding, multi-region — only when an ADR proves the benefit exceeds the risk and cost

Typical timeline for remediation: quick wins in 0–7 days, stabilisation in 1–4 weeks, scale validation over 1–3 months.