Toyman01 + Sized and said:
Condition is all that matters to me and I consider it in the order I don't want to work on.
Rust, upholstery, paint, mechanics, mileage, price.
Rust is an instant deal breaker. BTDT, never again. The others will depend on the price.
I bought our Suburban with over 300k on it. Changed the fluids, fixed a broken fuel sending unit and took it on a 4000 mile vacation. My wife drives it daily and it has almost 375k on it now. I will run it into the ground and sell it for scrap.
I bought my XJ at 250k. No plans to sell it. Ever.
My youngest's Colorado was bought at almost 300k. It was a company car so I knew its history.
The only vehicle I've ever bought with low mileage was my RV. It is 25 years old but only has 55k on it.
This brings up a good variable to discuss.
It depends on what you're going to do with it. If you're going to buy something cheap and run it until it's worthless, you can push the mileage higher.
My jam is to buy something low-mileage and somewhat desirable (at least has a broad market) at the bottom of it's depreciation curve, drive it for a few years, then put a coat of wax on it and sell it for pretty much what I paid for it. It means I often spend a very long time looking for the unicorn.
My current Branger (94 Mazda B4000). It's the whole kit and caboodle of unicorn-ness. It has every single option except automatic transmission. Power everything, power sport seats, pushbutton 4x4, first year that the B4000 was a Ranger, and it was a rust-free FL truck with only 84k miles which I bought in PA. I now have a 114k mile truck, still with no rust in PA, that I know will bring what I paid for it during the current fever pricing. But if you're looking for a vehicle that you expect to pay $X and run it until it's worth $0, I still recommend low mileage, because for your $X you will likely get more life before it reaches the $0 mark.
It is very rare that I don't make back at least 90% of what I paid. I did take a bath on one, but some I've made 200% of what I paid or more because I waited for the "right" vehicle.
But, if you're looking for a forever vehicle that will last you a long time, the bottom line for me is that lower mileage means less time with a butt on the upholstery, less wear on the driveline, bearings, fewer miles trying to jiggle spot welds apart and metal fatigue, fewer miles of rain water being jetted into pinch welds, fewer rock chips on the fenders, fewer times the windows have been put up and down, fewer electrons passing through the sensors, fewer cycles of the injectors... you get the idea. Basically, it likely has a longer time before I have to start throwing money at it to fix things.
Every vehicle has a fixed life before it starts falling apart, and mileage is a very good indicator of how much life something has left. I personally choose to maximize the miles I have before that happens, hence why I choose low mileage.