Recently SharePoint forum user posted a query about SharePoint Document Library and List item limitation. When search technet founded that.
Each document library can store 2 million records, if you need very large document libraries by nesting folders.
Each List can store 2000 items however you can create nested folder to overcome this limitation.
Each List / Doc library can create 2000 folder. If you have beyond a thousand entries each folder Folder do not perform
For more details visit