Plan a caching strategy

Help me plan a caching strategy.
Inputs: hot path; data freshness needs; stack; traffic.

1. Check whether caching addresses the measured bottleneck.
2. define scoped keys, TTLs and invalidation paths.
3. plan stampede protection, degradation and rollout measurements.

Deliver: Verdict, Cache plan, Keys and TTLs, Invalidation, Failure and stampede handling, Measurement, Rollout.
Clarify critical gaps, separate facts from assumptions, and do not invent data, citations or completed actions.

My material: [fill in here]

Before you start

Provide hot path; data freshness needs; stack; traffic.