The initial storage cost of the search index on a fresh installation of Windows 11 is minimal, only a few megabytes. When a sizable work folder is added, the index expands, but it does not revert to its original size after the folder is removed. The search index is stored in Windows.db for Windows 11 and Windows.edb for Windows 10. Windows 11 has two indexing modes: Classic (default) and Enhanced, with Classic indexing Documents, Pictures, Music folders, and the Desktop, while Enhanced scans the entire PC. The index includes file names and content, allowing keyword searches. Users can measure their index items through Settings without special permissions, while file size requires administrative access via PowerShell. An index under 30,000 items is acceptable for average users, while performance issues may arise beyond 400,000 items, with a technical ceiling of one million items. In an experiment, the index grew from 462 items and 6.71 MB to 3,466 items and 18.66 MB after adding 3,000 text files, but remained at 16.81 MB after deleting those files. To reclaim disk space, users can exclude specific folders from indexing and rebuild the index, which can significantly reduce its size while retaining the same number of items.