Because my professional use % of my car can vary from quarter to quarter, I enter my car expenses (e.g. insurance, maintenance, etc.) on a pro rata basis per quarter. How does this work for car expenses that are ‘applicable’ for a year? (e.g. car inspection, maintenance, insurance, etc.) if you have not used the car for professional purposes at all during a quarter? Can you enter these (pro rata) in a later quarter when you have used the car for professional purposes? Thank you in advance for your answer.