If you plan on growing your business, even if you are doing everything yourself, consider this when setting up your office systems:

[Perhaps not an actual rule.... but a pretty darn good tip.]

When planning a system, or considering whether to change a system, ask yourself, will this system’s integrity hold up with 10x more use? and then you can follow this question up with: Could someone else stepping in to do this be easily oriented?

Moral of the story, plan for growth all the way down to your filing system :)