What is a branch in Git and why is it cheap?

A branch is a movable pointer to a commit. In the repository it is just a small file such as .git/refs/heads/main that holds a 40-character commit hash. Creating a branch writes that one file; no project files are copied.

When you commit on a branch, Git creates the new commit and moves the pointer forward. HEAD tells Git which branch is current.

git branch feature/login       # create
git switch feature/login       # move HEAD to it
git switch -c feature/search   # create and switch

Because branches cost almost nothing, the normal workflow is to create one per task or fix, work in isolation, and merge it back through a pull request. Branching and switching take milliseconds even in large repositories.

A branch is only a label; deleting one does not delete the commits, as long as another ref reaches them.

Takeaway: branch freely, one per piece of work.