After reading the post yesterday about my paperless office, Twitter user @bhdicaire asked me if I could post some of the rules I use in both TextExpander and Hazel to keep my paperless office setup humming.
Here are a few:

This Hazel rule is a name-based rule to move files about my car service to a Car > Service directory.

This Hazel rule is a content-based rule to move files about my car service to a Car > Service directory. Note that when I process files using content, I add other rules to rename the files as well.

Here are the file-renaming patterns for the step above.

Here is another content-based rule. This one takes a scanned electric bill, evaluates it based on the string "PECO", renames it and moves it.

This is a rule that uses part of the name ("taxes") but then makes sure they're mine before moving them to their final resting place. I'm sure this was for an edge case when I was scanning the hundreds of documents that eventually made up my paperless archive.
The rules are pretty simple. I don't have a lot of directories that things get filed into but it is key that you can find things easily once they're filed. Don't create folders that are too deeply nested or you'll run into trouble.
I have about 30-35 Hazel rules set up to handle almost all of the variations that come in via scanner. The rest are handled through two simple TextExpander rules that set up a file name based on month or day. I just modify them with keywords to help Hazel figure out where they go afterwards.
I hope this little excursion into my brain wasn't too terrifying.