Running GitHub Actions Efficiently

Actions minutes on private repos bill against a monthly included quota; public repos are free. So cost concentrates in private repos, and a handful of workflows usually dominate the bill. This skill is the checklist for finding and fixing that waste. Every fix below preserves what CI actually verifies — none of them trade away coverage.

First, know the one number that dominates everything

Minutes are billed per job, rounded up to the minute, times a runner-OS multiplier: