TRG (Tire Rack Guy)...consumer advocates, financial planners, anybody who analyzes the cost of buying and owning a car will tell you that keeping an existing car running for a long time (10 years) is almost always better than buying a new car.
An example helps clarify:
Let's say you bought a new ST for 28,000 in 2001. For the sake of keeping our analysis simple, let's say you paid cash.
Let's speculate that the 2001 ST was worth 50% of it's new price when it is 4 years old. So, at the end of year 4, you've "used" about $14,000 worth of ST, plus whatever you spent on upkeep. That works out to $3500/year+. As the car gets older, it doesn't loose value as fast, so lets say, for the next five years of ownership, the car loses $2000 of it's value each year, until it's basically worthless.
Now you are in the "sweet spot" of deprectiation. The car is not losing value very quickly anymore. Each year you keep it, you use up about $2000 worth of the remaining value of your ST every year from now on.
If you buy a new one for a similar price to what you paid last time, you are back to using about $3500 worth of ST every year. Plus the transaction costs (taxes, higher insurance, any shortfall on your trade in).
In this simple example, if you can keep your current ST running for less than $1500/year out of pocket (the loss of value cost difference between the two vehicles), you come out ahead by keeping the old one.
The intangible costs (your happiness with the vehicle, having a reliable vehicle that you trust, etc.) have to be factored in. If these issues are important to you, you have to look past the raw numbers.
