I've used the Rules Wizard to define many rules, some of which are quite old and probably obsolete. Is there any way to tell whether and when a rule actually found a match?
A good way to track the effectiveness of your rules is to apply a category to each message that a rule handles. Use the assign it to the category category rule action and, for the category, specify the same name as the rule name. You can then use Advanced Find to locate any messages in your mailbox that a particular rule handled.
If you use this technique, you should include the code that Listing 1 shows in the ThisOutlookSession module in Outlook Visual Basic for Applications (VBA) to strip any categories from outgoing items. If you don't use this code, outgoing messages will have the same categories that your rules applied, which could prove embarrassing in some circumstances.
Tracking the effectiveness of rules that move items to a public folder is a little trickier because you can't use Advanced Find to search across the entire Public Folders hierarchy. One solution would be to include a move a copy to the specified folder action and specify a folder in your mailbox that you use just for collecting copies of items sent to public folders; include the category action, too. To keep this folder from becoming cluttered, set the folder to automatically archive all items older than a week or so (or whatever interval at which you plan to check the folder to monitor your rules) and to permanently delete items when AutoArchive runs.