Replied to [gs]s message :
is there a setting to delete oldest items automatically beyond a given
limit ( number of items, quota, or date elapsed)/
Start | RUn | Regedit :
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
Right side, create a new REG_DWORD value named MaxRecentDocs then double
click it.
Switch to "Decimal" and enter the number of maximum recent documents.
Click OK
Restart Explorer.exe
Good Luck, Ayush.