[danielweber]

Gas is about $1,000 a year, very roughly. (10000 miles @ 30 mpg @ $3 a gallon. You can of course change those numbers in either direction.)

8 years may not quite pay for a new battery. It depends if you can extract any value from the used one.

[rprasad]

In California, where most fuel-efficient/electric cars are sold, gas ranges between $3.50-$4.00/gallon (or above $4.00 during periods of "high demand"). Gas in the areas targeted by Tesla (i.e., Beverly Hills) starts at $4.25 and goes up from there.

Also, very few cars on the road anywhere in the U.S. get close to 30mpg, excepting hybrids and 2012 or 2011 versions of some (but not all, or even most) smaller sedans. The most popular models of the most popular sedans of the last decade, i.e., the Camry, Accord, and Civic, do not get 30mpg--they tend average around 22-25mpg in real-world conditions. MPG is even worse among the luxury cars that compete with Tesla.

Consequently, the gas cost savings experienced by Tesla owners would be significantly greater than $1,000/year.

[danielweber]

Where gas is more expensive, people will tend to have cars with higher MPGs.

MPG is even worse among the luxury cars that compete with Tesla

That's the key question. If someone is getting a Tesla because they care about mileage, they probably were not driving a 20 MPG car beforehand. If they were getting it to show off that they can afford a $100,000 car, then maybe they were.