I just keep a record of vehicle mileage on a word document - Jan 1 and Dec 31. That's if your vehicle is used ONLY for business. Otherwise, you can keep a daily log on a calendar or whatever. Yes, the IRS will "go after" the non-reporters of 1099 income. They simply send you a notice that you miscalculated (if they think it might have been a mistake on you part - like not including income reported on 1099). They will have amended your form and you owe ($$$$); plus penalties and interest. There's really not that much agent time or expense involved - it's all automated. This actually worked to my benefit last year. They recalculated my taxes and sent me several hundred dollars back as Overpaid Taxes. Now, if they suspect fraud, that's a whole separate discussion.