By Scott Burns

The Burns family Prius, which we treat like an adored child, is now 8 years old. It will turn 100,000 miles before year end. Today the odometer reads 95,500 miles. We've run the last 2,600 miles at 44 mpg. While it usually did 43 mpg when we lived at the 7,000-foot altitude of Santa Fe or in the dense city traffic of Dallas, it seems a bit happier living the country life in Dripping Springs, Texas.

With gasoline once again closing on $4 a gallon, the Prius brings major pleasure at the gas pump. A typical fill-up runs about 8 gallons. It requires no more than three visits a month, often just two.

This isn't to say that our Prius is entirely at ease here. As it weighs a dainty 2,765 pounds, I try to park it in far corners when visiting places such as Tractor Supply. There, it could be unwittingly crushed by a long-cab Ford F150 or similar mastodon. It's also good to be extra-careful in school zones where harried moms in Chevy Suburbans might not notice the car's sublimely modest presence.

Yes, this is a pre-trendy Prius. The 2003 is the last year of the first body style, a somewhat dinky sedan. It's pretty much a brown wren of a car compared to the fastback style of the big-hit Prius since 2004. Over the years we have learned that it's OK for long trips, but just OK. It really comes into its own for local trips driven at 40 mph to 55 mph on smooth country roads. That's when it's comfortable. That's when it sips gas. Its other big virtue is parking: There is no such thing as a parking spot that is too small or too difficult to swing into.

Since 2003 I've written a dozen columns focused on the idea of fuel efficiency and what becoming fuel-efficient could do for our country. (A lot.)  With more than a million sold to date, a brand-new generation of Prius will soon be available. Lexus has already launched its CT200h, so it is now possible to get 40 mpg in style and comfort. Equally important, we now have a lot of hybrids from which to choose.

Has the early Prius brought any worries? No. When I first wrote about it, dozens of readers said every drop of fuel economy would be swallowed by the cost of replacing its expensive battery. But that didn't happen, for me or most other owners. Today, there is every indication the battery will last well beyond its expected 10 years. Indeed, if you read the ads for other 2003s on www.autotrader.com, you'll find cars with well over 100,000 miles still using their first battery. We're thinking our Prius will eventually become a grandchild's first car.

Has the Prius been hard to service or had costly repairs? No. Other than tire replacements and the regular scheduled service, the car has only needed one repair. Yes, it was expensive – $2,123 – but it was the only repair in eight years and 95,000 miles.

Is the car worth anything today? You never know. Originally purchased for the $19,995 MSRP, the car is now supposed to have an NADA trade-in value of $4,200 and a clean retail value of $7,300. Both of those figures are lower than cars offered on www.autotrader.com. There, only 18 cars of that Prius vintage were for sale in the entire country, with an average asking price of $8,985. If it sold for $6,000, the depreciation would be $14,000 over eight years, or $1,750 a year. If it sold for more, the depreciation would be still lower.

That depreciation figure is important. We all complain about the price of gasoline, but the largest cost, by far, of owning a car is depreciation. The 2010 study of automobile ownership costs done by AAA, for instance, says we can expect a typical small sedan (Ford Focus, Honda Civic or Toyota Corolla) to cost $2,384 a year in depreciation. A mid-sized sedan (Ford Fusion, Honda Accord or Toyota Camry) would cost $3,451 a year in depreciation. Needless to say, an SUV or minivan costs still more, but most people buy those vehicles for their carrying capacity, not their fuel economy or low cost.

Would we buy another? Yes, but we've got miles to go on this one.