A little background:
I bought this car in early 2018 with a little over 23K on the odometer. It was in excellent condition, but I didn't like the tires. I replaced them with Pirelli P Zero 235/40 R18s. When I went to Discount Tire a week ago to have them rotated, the two on the rear had severe inside edge wear, sufficient to require replacement. The other two were OK, but getting a little low in tread depth, so I changed all four. The shop suggested an alignment problem, so I took the car in for an alignment. The alignment was basically perfect, so ?
I reviewed my records and found that (shame on me) I'd only had them rotated once, at a bit over 39K. So the tires had been on the front for 16,000 miles without rotation.
The shop had set the tire pressure at 36 psi, per the door sticker. The alignment shop suggested that the excessive wear was a result of underinflation, and urged that I run them at 42-44 psi. Max on the tire sidewall is 50 psi.
Whose recommendation should I follow? The ride at the higher pressure is a bit firmer, but not objectionably so. Advice is welcome. TIA!