for EG 195/55 R15, i would like to suggest a 30psi = 210kpa. +/- 5 at good tyre.for old tyre more than 2 years, they said need to pump more??? emm..maybe the tyre compound is getting harder.logicly, the harder the tyre, lesser the pressure to maintain comfortability.
BUT for small compact car, 14" must be pmp at 180kpa.if not, you'll experience a harder impact unless you need a fst and sharp cornering
nowdays, newest petrol station use digital accurate pump. i assume this will give a perfect pressure needed cause the pump will +/- its pressure till get the exact setting on screen..nice suff.