Git's popularity stems from its unique approach to version control. Instead of storing file differences like older systems, Git saves snapshots of the entire project state during every commit. This design ensures repositories remain compact despite extensive histories. The core question is how Git manages this efficiency, avoiding massive disk usage while maintaining full project history and fast operation for developers working on large codebases.

At the heart of Git's architecture is its object model. When you add a file, Git stores its content as a blob. Directory structures are captured in tree objects, while commits link everything together. Crucially, Git uses content-addressable hashing. If a file's content hasn't changed, Git reuses the existing blob instead of creating a new one. This automatic de-duplication is the secret behind its space-saving capabilities.

Changes flow through three areas: the working directory, the staging area, and the commit history. Running `git add` creates a blob only if the content is new, otherwise it references the existing object. The staging area tracks these references. When you finally commit, Git builds a new snapshot pointing to these objects. This means most data is shared across commits, keeping repository sizes manageable even as projects grow over years.