Cannibal,
If you are using Lotus 4.xx, default size limit is
1 Giga and you can manually increase that for 4 Giga.
With R5 by default you do not have this limit anymore.
400Megas is very common size of end users mailbox...
You can also run compact or ask your employees to do archive if you are running out of diskspace.
Regards: Mika