I've got a 2007 Chevy Impala that I bought at a police auction (hey mustache, looking a little full there). I've had it about a year. The tires I bought it with are larger than standard for a sedan and all season. When I got my oil changed at Wal Mart, the guy advised me my tires were looking a little worn.
How do I actually know that I need to replace my tires? Should I look at getting a different size, assuming I could mount a narrower tire on my rims? The comments to some of the recent car posts/threads suggest that certain brands of tires would provide improve gas mileage and offset potentially higher costs. Has anyone done the math on that? Anyone ever bought used tires? Discount tires? Sketchy craigslist tires?
Note, my job situation is in extreme flux and I may go from putting 1500 miles a month on my car to 200 miles a month, if I change positions soon. Ideally, I'd like to get a new job, not buy tires, sell the car and let the next person deal with it. My sense is at the low end of the used car market, spending $800 in nice tires adds approximately $0 to the resale value. How do I know how long I can put off this purchase? I don't want to be dumb about the risk of having a tire blowout and causing an accident.