Glossary
5,000 item list view threshold
The list view threshold is SharePoint's limit of 5,000 items returned by a single view or query. The list itself can hold millions — the limit is on what one view returns at once, not on how much you can store.
This is the single most misdiagnosed thing in SharePoint. People hit it, conclude their data has outgrown the platform, and start planning a migration to a real database — when the actual fix is indexed columns and views that filter to under 5,000 results.
With views configured properly, tens of thousands of items are unremarkable. The genuine reasons to leave lists are enforced relationships, row-level security and transactions — not volume.