Just changed the Pirelli's on my 2018 MB. Date code was late 2017, so I figured about 7 years old. The car only has 18,500 miles on it and the tires measured 9/32 of tread left.
The difference in ride is not dramatic, but noticeable. Much better in some situations, so I surmise the tire compounds were hard.
Got the chance to look at one of the unmounted tires and sure enough, there were small cracks in between the tread grooves.
I'm pretty sure this Florida heat had a negative effect on the tread compounds, so I don't regret the choice.
I'm also planning a possible trip to PA mostly on I95. Speeds during that trip will surely exceed 90 mph in some sections.
I hated spending the cash, but feel much safer for this trip.