How do you drive a Toyota into the ground, anyway?
Sorry for tipic creep, but most Toyota's will last forever if properly maintained. Just think of the car as a computer... and spend the money. You wouldn't skimp on HDD, RAM, or O/S upgrades if you needed them, would you?
I built and maintain my own PC, and I do as much work as I reasonably can on my own car. What I hate is when something needs to be diagnosed and fixed, and my choices are trying to do it myself after hours or taking it to a pro: the former carries the risk of being off the road longer, while the latter will cost a lot more. The pressure is much worse when there are no public transport options to get to the client, of course.
Just take the car to a good mechanic twice per year, and don't skimp on the important stuff.