The original title is: "Why your GitHub Actions CI is slow (and how to speed it up)"

Short summary

GitHub Actions workflows waste minutes through common misconfigurations. A scan of 35 popular open-source repos found 91% lack concurrency control, 94% have no job timeouts, and 63% run full test suites twice per PR. This guide provides exact YAML fixes: scope triggers by branch, add concurrency with cancel-in-progress, enable caching, slim matrices, filter paths, and cap job timeouts at 15 minutes.

• •91% of scanned repos lack concurrency control; cancel-in-progress can triple queue efficiency
• •Eliminate redundant runs by triggering only on pull_request for same-repo branches, not both push and PR
• •Enable caching, filter paths, add job timeouts, and slim test matrices to cut CI minutes by 50%+

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