If you drive your car for business as an independent contractor or unreimbursed employee, you need to document your business mileage. I know this is a broken record with me, But you need to keep an auto log with dates, mileage, odomoeter readings from your car, where you went and how it related to business. It is also good to have a couple of independent invoices (like tire and auto repairs) to validate your odometer, but not essential. The auto log is the one piece of taxpayer generated unsubstantiated documentation the IRS has to accept. At least keep a calendar with this info that you can use to substantiate your mileage. It can save you aggrevation later.
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