Most developers rely solely on .gitignore for excluding files, but Git supports three distinct ignore mechanisms. The traditional .gitignore file gets committed to the repository and applies project-wide, making it ideal for shared ignore patterns. However, this approach doesn't cover personal or machine-specific exclusions.

The .git/info/exclude file offers per-repository customization without affecting the shared codebase. This solves the common problem of wanting to ignore local files like personal notes or IDE configurations that shouldn't clutter the team's ignore list. Meanwhile, ~/.config/git/ignore provides system-wide ignore rules, perfect for universal exclusions like .DS_Store on macOS or editor swap files.

Git's check-ignore command reveals which ignore file handles specific patterns, showing the source and line number. Users can customize the global ignore path through git config --global core.excludesFile, then verify exclusions with git check-ignore -v filename. This layered approach gives developers granular control over their version control workflow.

Understanding these three ignore levels prevents unnecessary commits of temporary files while keeping repositories clean for everyone involved. Most teams stick to .gitignore alone, missing opportunities for better local workflow management.