|I just finished doing my TY 2020 taxes. During the year I sold my 10 year old car. TurboTax had me go through my mileage records for the entire time I'd been using the car for notary work, and figure out how much depreciation I had claimed via the standard IRS per-mile cost, and compared that to the actual depreciation of the car. It turned out my actual depreciation was less than the IRS allowance, so I had to pay about $50 in federal tax because of that.|
So keep you mileage record for as long as you own the car, plus several years while the IRS is thinking about whether they want to do an audit or not.