Buy a used car or drive paid off Tahoe?

Due to a new job, my wife will now be driving 40 miles to work. Her previous job (she was laid off) was only 5 miles away. She currently drives a 2002 Tahoe w/ ~100k miles, and I am torn on if we buy a $5000-6000 used car w/ ~25-30mpg or just have her drive the tahoe. I am sure we aren't the only ones to go thru this.

On one hand: drive paid for tahoe and have the higher gas bill, along with the wear and tear on SUV forcing us to by a newer used one 4 years down the road.

On the other hand: buy a third vehicle (5-6k), and save the miles on the tahoe with with the added cost of maintaining a 3rd vehicle.

Please give me your feedback...thanks!

Trade it in.