For example, if you deduct your mileage, it's critical to have a log that meets IRS standards--meaning it includes dates, odometer readings, trip details, etc.

Keeping a mileage log The IRS tends to be strict in its documentation requirements for business mileage deductions.

The log should have accurate accounts of your mileage and is the document used to validate your driving deductions if you are audited. Estimating the values on your taxes is no substitute for ...

The mileage log should include the date, an explanation of the trip, the starting mileage and ending mileage along with a total of the miles covered.