The Vault Size History plugin enables Obsidian users to visualize the growth of their vault by displaying a graph that tracks the number of files over time. It allows customization of file categories, enabling users to group files by folders, patterns, or regular expressions for more detailed insights. Users can toggle visibility of specific file categories on the graph, adjust date formats, and define exclusive or inclusive categories for precise analysis. This plugin is ideal for users looking to monitor changes in their vault structure and content over time.