Self-employed - Mileage deductions

[MelissaCR]

My husband and I are both self-employed (in different fields).  We deduct the mileage on our cars.  Last year, we traded in my husband's car.  I primarily drive the new car; he primarily drives the car that I used to always drive.  However, we switched cars during the summer month and plan do that that in the foreseeable future (he needs the ventilated seats).

We kept track of our business miles driven on each car and which business those miles were specific to.

These are our only two cars, and they are each available to us for personal use as well.

Should we be using this level of detail and specificity, or should we "assign" a car to each business?  He's putting about 30k - 35k miles on the cars, while I only put about 8k - 10k. 

[ThomasM125]

You do need to assign the correct mileage to each vehicle. When you eventually dispose of the vehicles, you will need to calculate the depreciation applicable to the vehicle based on the business miles driven in order to determine the gain or loss on it's sale or abandonment. That gain or loss will be taxable or deductible by the business.