Having installed tires for years, amongst other things, I observed a general set of rules that I incorperated into my own thinking. Tire pressures: 32 psi in a 35psi max - 35 in a 38 - 38 in a 41 - 40 in a 44 - 46 in a 50 - 75 in a 80 - 90 in a 100 - now for trucks with the higher psi rated tires, some are very picky on pressures, for example, a Ford F350 dually we would normally set the fronts to 70 and rears to 85 (80 psi max rated sidewall) and definately recommend the regular rotations. Doing that we would often see tires that were rated for only 50k miles regularly get over 100k before needing to be changed out. Now having said all this... lol... this is Ecomodder, and a working allowable increase beyond what I have observed is more the norm. My own Impala with 44psi max rated sidewalls are run at 44 psi so far. When I find a close reliable source of nitrogen filling, I plan on bumping things up to 50 to observe the changes. Old school thinking (and incorrect gas station air gauges) suggested that over inflating a tire would lead to more wear at the center or crown of the tire. This is still true in extreme cases (incorrect gas station gauges a prime culprit) as is wheelspin during slippery conditions. Personal note, wheelspin while fun, does induce increased tire wear
Additional info - please note that vehicle manufacturers place a small plaque or datacard most often on the driver's side doorjam, which includes info on VIN and certain specs, including tire size and pressure recommendations. Many Toyota/Honda/Subaru specs are way below the tire max sidewall settings. Several domestic makers have done similar in the hopes of making the ride more supple, and less stiff. Ford Explorers used to have a dismal 26 psi rating for the tires, and subsequently had many rollovers and tire failures that they tried to pin upon Firestone. Well the truth came out when other tires were treated to the same low pressure and although Firestones used had a weaker sidewall (increasing the failure rate some) it was shown that the low pressure was to blame. Further testing showed that the Explorers were better off running tire pressures at the recommended 32psi (in a 35 psi max sidewall rated tire) and in some cases, even going up to a 41 psi max rated tire and using the 38 psi setting (although that was often set back down to 35 psi) Your vehicle datacard will tell you what the manufacturer thinks is the best tire pressure, time and experience will give you the tire pressure best suited for your mindset, driving style, and vehicle.
Good luck.