I’ve seen a wide range of allowed sizes. A recent client had a warning go out at 400mb, but did not stop incoming or outgoing mail. The worst offender, with an 800mb mailbox, had a rule that put messages from System Administrator (like the one saying the mailbox was too big) straight into the trash.
Another client has at least 10 users with over 4gb each. They regularly send and receive large PDF and JPG files. While not wanting to restrict users, their biggest problem is disk space on the Exchange server and tape to back it up. They are ready for aggressive archiving.

We’re running Exchange 2000(SBS) and set some quotas individually (a couple at 400MB), but the rest are set at 200MB, prohibiting sending new email at 210MB, but never restrict receiving email.

Still on poor old 5.5 b, and up until about a year ago I didn’t have limits on. Most of our users by habit keep their boxes to 150-200, but there are some that deal in large attachements that don’t clear out the attachments (especially sent items). After going through the list of mailboxes and deriving a breaking point I came up with warning at 750MB and a send limit at 800MB. I only have a couple of users that hit this (we have about 50 users and have the silly 16GB limit to deal with, we aren’t running enterprise). So far this has kept our store right around 12GB. I also use exmerge to yank the last year’s sent items to PST archives.

One caution about using small mailbox quotas:

Depending on the regulatory requirements for your organizations, you may be required to have secure control over email for a specific amount of time. It could be for litigation purposes, maybe auditing etc. As soon as you shrink the mailbox size to something so small that people start creating .pst’s you no longer have control over those emails and may be in contravention of the regulatory requirements. You also can’t control what happens to the pst’s either and someone could inadvertently “loose” that pst with a bunch of confidential information in it.

This certainly won’t apply to everyone, but it is something that you need to be sure of before you start shrinking mailboxes.

One caution about using small mailbox quotas:

Depending on the regulatory requirements for your organizations, you may be required to have secure control over email for a specific amount of time. It could be for litigation purposes, maybe auditing etc. As soon as you shrink the mailbox size to something so small that people start creating .pst’s you no longer have control over those emails and may be in contravention of the regulatory requirements. You also can’t control what happens to the pst’s either and someone could inadvertently “loose” that pst with a bunch of confidential information in it.

This certainly won’t apply to everyone, but it is something that you need to be sure of before you start shrinking mailboxes.

W2k and Exch2k. 35 users. I hadn’t bothered with limits until we hit the 16Gb limit! Not once, but several times.

I now have a 1Gb limit for those who need it but warn at 700Mb.

It took an offline defrag to get the Db back to 12Gb from 16Gb. There were howls of protest from many of the users who thought email was a filing cabinet. I sympathised, but that 16Gb limit had to be dealt with.

I now run the maintenance tool every Thursday and everything over a certain age is moved to the Deleted Items folder. Even if nothing is moved, Users get the warning email which focuses their minds on deleting old stuff.

HTH

I am a public school district with 1200 mailboxes. For teacher accounts I give a 25 MB limit. I give 50MB to 100MB for administrators and sometimes more if the needs require. I have used PST files for people with more needs as well but I am currently looking for an archiving/migration utility to pull the PST’s back into Exchange. I never restricted an account from receiving messages, just sending. That why a user won’t miss an important message but is forced to clean out their mailbox if they want to send email.

300MB notify, 400MB stop send, 500MB, stop receive. tried smaller but they just create PST files and move messages to that.

btw: the 16GB limit has been moved to 75GB with Exchange 2k3-sp2. Check out the KB on that.

Right now we have 425 mailboxes. Our limits are 640MB for send, 740MB for receive and warnings at 240MB. I am looking to lower them significantly though as most users see email as a file storage and CC everyone and their neighbour. As you can imagine, this can put a tremendous load on the server (currently using early gen p3′s).

We are on Exchange 2003 with 1200 users. I have a 500mb limit, no send or receive, with warnings starting at 450mb.

We run Exch 2003 with 535 users. Everyone (admins included) is set to 200 MB limit up from 25 MB when we were on 5.5. I have warning at 195, prohibit send at 200 and prohibit send/receive at 205.
We are starting to run mailbox maintenance on Inbox, sent and deleted to show them how much junk they are keeping. after about a month we will start having it removed from their mailbox entirely.
We have message size capped at 5 mb across the board. We are a printing company so many big files flying around that is why we tell users to use ftp, better means for transferring large files.
We greatly discourage pst’s, we don’t back them up at all but some still use them.
I have been playing with GFI Mailarchiver and am going to upgrade to the newest release v.4 which doesn’t require SQL anymore and you can set mail retention policies on the archived mail.
Also have been looking at Quest Message Stats and Spotlight to try to get a better handle on everything.
email is the life blood of the company these days.
they complain but then again they complain about everything.