Outlook Draft Folder limits
The Draft Folder in Outlook is just like any other folder in that, if you wish to store multiple items in it, you may.
The total item and folder limits depend on the version of Outlook as listed here.
Outlook 2010, 2013 and 2016:
- 100,000 items per folder
- 500 folders total
Outlook 2007:
- 50,000 items per folder
- 500 folder total
Note that even approaching these limits may impact performance.
Details of Outlook limits and performance issues can be found here: https://support.microsoft.com/en-us/kb/2768656