2010 Toyota Prius - 42mpg - runs good and no visible rust

This was a car for the kids but they all left the house. I have been driving it off and on for the last year without any troubles.

The 42mpg is from all in town driving on the last tank of gas. When on the highway/interstate it is closer to 25-35mpg depending on speed.

Recent service:

no check engine lights

AC and heat work great

changed oil (I can't turn the oil maintenance required light off)

rotate and balance tires

new battery over the winter

New tires a 2-3 years ago (But it has not been driven a lot so they are pretty good)

Mileage calculation for the last tank of gas:

217929 - 217528 = 401 miles on last tank

401 / 9.469 = 42.35 MPG