Our $16,000, 38 mpg small car saves us 25 gallons of gas a week over our 18 mpg vehicle . Times that by an average of $3.50 a gallon you get $87.50 per week. Times 4, you get $350.00 per month, times 12 you get $4200.00 a year. Over 5 years you get $21,000 dollars, the car more than pays for itself. We save our $45,000 dollar vehicle and the environment.
If you are putting 45,000 miles a year on your "spare car", how many miles are you putting on you main car?