hotpath — never optimize on vibes

The skill is the discipline: measure → change one thing → measure the same way → report the delta or revert. An optimization without a before/after number is a rumor. Most "obvious" performance work fixes code that wasn't hot and misses the query that was.

When NOT to use

• The answer is wrong, just slow to be wrong → sleuth.
• "Will the architecture handle 100×?" → headroom.
• The UI looks slow but no measurement exists yet → that's your step 1, not a reason to skip measuring.

Workflow

1. Define the target