I got my car in Dec 2016, came with very high PSI, 39 and 36PSI (recommended was 38/35 or 33/30 for 'Komfort'.
As I got my car in the middle of winter...I lowered PSI to 38 and 35 (by poking valve).
I do have a handheld tyre pressure device though, that shows digitally the PSI.
As temps went up, guess what? PSI went up too! At first I was wondering, is it creating it's own air?
So for a good 6-7 months I didn't have to put any air. Not only did pressure not drop, it went up as temps increased! So got the car in Dec 2016, only put air around Aug/Sept 2017.
I usually check pressures every 2-3 weeks...and when the temp drops cold, PSI also drops easilly 2-3 PSI. And add air every 2 months or so. It used to be 20p at Tesco, now 50p
I do approx 6k miles a yr.
I tend to run pressures 37/34, and when it goes down to about 34/31, I top it up.
All tyres seem to fall equally pressure wise. Had the Tyre pressure warning ping once in my
Ibiza, it was as false warning. All pressure were 'normal' after I checked with my handheld device.
In my Leon, the only time it pinged, it was a puncture, and the affected tyre was 20PSI, all others 30+ PSI. It was a nail in the tyre. The car was correct.