Seperate Business Credit Card

If you use one separate credit card for ONLY business expenses, it's MUCH easier to keep track of what you can deduct. It doesn't have to be a special card, or one with a large limit (particularly in a single therapist business). I just got a store card Visa.

Also, I believe, although I am not 100% sure, that with a card used only for business, you can deduct interest as well. That can be a big help for large purchases that you can't pay off in one month.