Each year you prepare a tax return for your client, Sebastian. Sebastian started a new business in January of 2019 delivering groceries to elderly clients. He uses the family van they have personally owned for years to make the deliveries. The family also use the van for personal purposes because they all cannot fit into the Toyota Prius they also own. It is now March 13, 2020 and you are meeting with Sebastian to gather information to prepare his 2019 income tax return. You ask him to provide the amount of business miles driven in his van during 2019. You are planning to use the standard mileage method to calculate Sebastians deduction for transportation costs. Sebastian states I dont keep track of my miles. He pauses to think, then says I guess I drove about 4,000 miles in 2019.

What would you say to Sebastian? Can you deduct the mileage as a business expense for 2019 on Sebatians income tax return? If yes, describe a legal method for Sebastian to document the miles. If no, describe why not. If no, explain to Sebastian what is required for 2020 to change the conclusion to yes. If yes, describe why.