My truck hit 430,000 before I gave up on it, but I probably should have rid of it at 400,000. Clutch, carb, a bunch of stuff had to be done then. Before that it was basically consumables, brakes, shocks, exhaust, timing belt, plugs, etc, not too bad at all.
But age is something to consider too, more than mileage in some cases. Everything rubber ages, including rad hoses, brake/fuel/vacuum lines, brake cylinders and calipers. Plus metal things corrode like rads and heater cores, and anything salt can get at.