Work productivity site Web Worker Daily has an interesting article on the bare bones of tracking your business expenses (especially timely as tax season—believe it or not— is right around the corner). Here's the bottom line:
The basic rule of thumb is that to be deductible on your taxes in the United States, an expense must be ordinary (common and accepted in your industry) and necessary (helpful and appropriate for your trade). Note that "necessary" doesn't mean "indispensable" to the IRS.
I must confess that I'm not as organised as I'd like to be with this, but that's where you come in, dear readers. How do you track your business expenses? Please share in the comments.