How to Use APM Tools Effectively

TL;DR APM = metrics + traces + logs — Use all three together. Auto-instrument first — Agents cover HTTP, DB, queues. Add custom tags ( order_id , customer_tier ) for business context. Use percentiles, not averages — p95/p99 reveal slow users. Averages hide problems. Distributed tracing — Shows cross-service bottlenecks via waterfall views and flame graphs. Alert on symptoms — Latency and errors (based on SLOs), not causes. Include runbooks. Sample intelligently — 10% of traffic, but 100% of erro