You haven't provided much information such as version of Outlook, email
account type, or even if these users are on a network or not.
On an AD network here, I cap almost all of the (Exchange) mailboxes at a
certain size. Some people must learn to manage that size and other users I
encourage to use a PST, though I make it clear that the PST is not backed up
by the network. It really depends on the user.
For example, our Receptionist does not need to use a PST and should never
approach her mailbox cap. She is expected to manage her mailbox size. Our
president however has no cap so a PST is not an issue. Our GM however does
have a cap and I have taught him how to create a PST, use it, and how to make
a copy for backup.
For our remote users who are never on-site and only use Blackberries, I
manage their mailboxes and PST's myself.
In our environment, whether or not a PST is created and used is dependent
upon the user and their needs.
