Sometimes when you change tires, it gets confusing trying to find a starting pressure. The max pressures are way too high, and what works for 23c tire feels stiff and awful when you shoe your ride with 28c tires. Enter the Bicycle Tire Pressure app.
The app allows you to input your bike type based on a few designs. For example, I created a profile for my Trek Madone as a "Race Bike." I entered the approximate weight, wheel size, and tire size. Then under the main screen I can enter my weight and get approximate rear and front pressures. For 28c tires it gives me 82 rear and 52 front. My preference is to run 10 psi less on the front so I generally ride 82/72 with that set up, but I am sure 52 would be okay up front just not to my preference.
The app is really useful for when you put some 38 slicks on the CX bike for the road and have no clue where to even start. It tells me 53 psi in the rear and 34 front. I tried it at 53/43 and it felt pretty good, a little high but a start.
You can even adjust the bike weight for panniers and racks front and rear. This could be very useful planning trips and touring.
If you ride a wide variety of tires sizes, give it a shot and adjust from there. See how it goes and let me know.