The monitoring stack that worked at 50 services breaks at 500. Patterns that scale aren't bigger versions of the small ones. They're different patterns.

Cardinality, retention, and query are the levers that decide what your team can know about the system, and how much knowing costs.

SLO targets need to match observability maturity, not a generic standard. Sometimes leveling up observability is the precondition, not a parallel track.