People have this notion that all cars must be pampered or they’ll immediately fall apart. Meanwhile, there’s a subset of the population that will, say, buy a brand new Porsche and take it to a racetrack every other weekend and beat the ever living snot out of it. It’s not uncommon to see dedicated track cars with 100,000+ miles. Granted, they go through oil changes and brake pads and suspension bushings and ball joints and whatnot, but there’s not a lot you can do on public roads to seriously impact the life of a vehicle. Even an occasional neutral drop or throwing it into reverse on the highway probably won’t do anything drastic. Heck, people think that doing a burnout in a rental is destroying it, but anyone who’s ever taken their car to a drag strip on DRs or slicks does burnout after burnout without any ill effects. Aside from things like worn tires and brake pads, there’s not a whole lot to fear from your average driver’s version of “abuse.”
Now, there’s always a risk that some numbskull drained the oil in his rental car and drove it for a month, but honestly who does that? And you run a bigger risk of something stupid like that when you buy a regular used car, because at least the rental company checked the oil frequently. Of course, that’s about all the maintenance you’re going to get from a rental car company, because a one or two oil changes are usually all that’s required in 20k miles.
The important thing, as with all used car purchases, is to have the car checked out thoroughly. Check for accident repair, busted interior pieces, etc etc, just like any other car.
The nice thing is that even if you don’t get a former rental, the fact that they’re out there will depress the used car market for everyone trying to sell that make/model. I recently bought a Sedona minivan, and I looked at a lot of former rentals. I ended up saving even more money by buying one from a chap who was having the hardest time unloading his because of all the cheap rentals out there.