I have read many articles stating that Outlook 2003 has a 20GB PST Limit, and several that state you can have as many folders as you would like as long as you keep the per folder count under 5000.
Here's my issue. I have a Director of IT who has a 2.8GB mailbox. Not huge, but good sized. What's interesting is that he has close to 95K email messages.
His mailbox performance isn't terrible. And for the most part he's happy. However, he's discovered that his "Advanced Find" doesn't work properly. Basically, it finds some of the items in his mailbox but not all of them. I have exported his mailbox to a PST, imported it into another message store and the results are the same. I have deleted and created the Exchange 2007 Index. There's no issues there. Advanced Find works fine on other smaller mailboxes.
What's the breaking point? Where does Microsoft say "We know it works up to this many items, and this size. Beyond this point, your on your own?"