There's too much bickering and parsing of words going on for my taste. In summation here's my take on it. As a person who's made a career of managing investments let me just say, cars in general, are not considered "investments". They are in fact a depreciating asset. There are exceptions to every rule, even with regard to investments. I should point out that investment grade automobiles certainly exist, but they are limited generally to exotic cars, classic or antiques. An example....a few years back a 1961 Ferrari 250GT California hit an all time high selling price of $10.9 Million dollars. Obviously there are other investment grade cars that occassionaly hit the market, just as an expensive painting by Renoir, Monet, Van Gogh, etc. might occasionally turn up at a Christies or Sotheby's auction. So what have we learned? Yes, cars can be an investment, but in the context of what this forum is dedicated to, the Ford Focus; it does not qualify as an investment... traditionally speaking. People often use the term investment in a very generic sense and that's about as close to investment grade that the Focus will ever come.
Having said all that, the point about minimizing depreciation isn't lost on me. The object is to retain as much value as possible, while at the same time getting the use out of the car. I'd also like to point out that even a 5 year old living room sofa has some value. Same is true with cars. We use them, they depreciate and eventually we replace them. Last I checked my Focus doesn't wash my clothes, clean my dishes or keep my perishable food from spoiling, so I stop short of referring to it as an appliance.