I think my biggest contribution to the general thrift of my household came from a flyer I saw a couple decades ago that worked out the math between buying a new car after the usual 7-year average that a person kept a car (then, at least), or holding on to a car until it was 10 or more, having the average in repair costs. I wonder if anyone else here saw that flyer - I think it made the rounds as much as could be expected, back before internet? It worked on the premise of, "What if you were offered a great job and all you had to do to earn your paycheck was drive the unattractive company car - wouldn't you love a job like that and here's how much it would pay you." The bottom line became amazing, as year over year the pretend family saved/"made" a bundle repairing the "company car" instead of buying.
I remember being fascinated by the math of it, and it somehow stopped me from admiring new cars! Since then, I've demanded 100,000 miles and 10 years out of every car I've owned. Right now the three 100,000-pluses in my driveway (when we're both home) are a reasonable-looking '95, a seriously unattractive '96 (which I bought in '97, with cash, for dd28's college years and won't sell - '96 was the year Ford's paint jobs famously peeled) and a nice-looking '97 (bought used from a co-worker at the paper years ago) that has the same body style as the next 3 model years, so is hard to peg for age. I complain about the repair shop sometimes (and they do know me there). Still - no car-payment book - priceless.