i was giving an example, not for every car

my tires have max allowed pressure 51psi and my car is very heavy. i pump to 42 all around for better handling, even wear, and gas mileage.

for most sedans with non-performance tires, 35psi is max allowed (printed on tires), so the pressure shouldn't be over than 35.

When you mostly drive in local, your pressure should be lower, in highway, it should be higher. in winter, you can pump higher, in summer, lower of course. if you load more, use higher pressure, vise versa... you see there are so many factors in tire pressure application.

Car manufacturers have recommended pressures printed on the sticker on front driver side door, however, it is a compromise of safety (they can's recommend 40psi since in case some people bought regular tires but pumped up to 40psi, the tires could blow up, then the manufacturer would be getting sued), comfortibility and drive-ability, etc. for individuals tho have full knowledge of tires/cars, as only as you do not exceed tire ratings, you are free to choose the best pressure for your specific situation.