If you have a Sainsbury’s petrol station anywhere near, the air machines are still free. I work at one part time and we’re the only petrol station in town with free air. Better invest in a small digital tyre inflator Brydo, I’ve got a Ring one which is excellent. There’s often a queue for the one at work!
I have one of those ring tyre compressors excellent reliable bit of kit had mine for over 4 or so years.
Tyre pressure to only be checked when cold travelling to the garage will give you a false reading, I must admit I am a bit over the top, I set the compressor to 2 or 3 psi higher than required, I pump up the tyres then let them settle for a few minutes, I then check them with an accurate digital pressure gauge and let the down slightly to the required pressure.
The manufacture recommend running at a slight higher temperate for high speed and towing still help to reduce the tyre temperature at speed, low pressure actual cause the tyres to overheat and blow out.
I have a device called a Tyrepal is measures and monitors the tyre pressures and temperatures as you our driving along ( it cost about £100), the valve caps are replace with sensors, they are mainly use by trucks, caravaner’s etc. You car get a kit for you car if required.
We set our caravan tyre pressures at 64 psi normally these will increase to 72 -74 psi and 20 -24 degrees C, on a very hot day they can go as high as 80 psi and 30 or so degrees C, this is well within manufactures tolerances. if we run the tyre at 61 psi we notice they will run at slightly higher temperature’s
Unfortunately I have suffered a brain injury and occasionally I get confused and often say the wrong thing.