based on about 9 yr. and 2 months of ownership and miles put on from 7,400 to about 238,000. It's been about 1 1/2 years since I've recalculated the maintenance expense...but it's been an expensive 1 1/2 years too...so I know I am still near the $100/month rate. Tires make up slightly over 50% of the maintenance expense.