Do I total all depreciation dollar amounts claimed each year, or is there a set amount allowed per mile for each year for depreciation purposes when figuring the sale? Say the car cost $20,000 in 2008, & total business miles are 5000 through 2018 (30% business use). Thank you!
If you used the standard mileage method in all years, then you would multiply the miles claimed by the IRS provided depreciation amount. You can find these amounts in IRS Pub 463, on page 23 (https://www.irs.gov/pub/irs-pdf/p463.pdf). Do note that the per-mile amount has changed over the years, so you'll need to figure out each year separately.