From the irs.gov topic no. 510. If you take the actual miles first year, you must continue with actual expenses.
Standard Mileage Rate - For the current standard mileage rate, refer to Publication 463, Travel, Entertainment, Gift, and Car Expenses or search standard mileage rates on IRS.gov. To use the standard mileage rate, you must own or lease the car and:
- You must not operate five or more cars at the same time, as in a fleet operation,
- You must not have claimed a depreciation deduction for the car using any method other than straight-line,
- You must not have claimed a Section 179 deduction on the car,
- You must not have claimed the special depreciation allowance on the car, and
- You must not have claimed actual expenses after 1997 for a car you lease.
https://www.irs.gov/taxtopics/tc510
