In keeping up with filing, I look for a time of day (or week) where my energy and attention aren't always at their top and use that time for filing and other "mindless" tasks. Then I'm still productive, but my mind isn't being challenged and I'm taking things slower since I'm not also sorting mail, writing memos, etc. My time to do one task at a time and not multi-task is when I file. Works well for me right after lunch, and I do it each day so I'm able to keep up and only take a couple of minutes a day. Gives me some movement to do before once again sitting at my desk, and keeps me from trying to take a nap.
good luck, whatever you end up doing.
CountriGal
Deskdemon Editorial Board Member 
