At his particular example, we will use the straight-line method of calculating depreciation. We will also assume that the limo has a useful life of six (6 years) because as per The National Household Travel Survey a car in the US is driven at an average of 15,000 miles per year so useful life is (90,000/15000=6
Salvage value is the estimated value that Bob is to be paid when the limo is sold at the end of its useful life (6 years). The salvage value of $5,577 is subtracted from the cost of the limo ($42,900) then divided by the number of years of useful life (6) to get the annual depreciation of $6.220.50 straight from the first year to the fifth year.