I am going to say that on average, when you start to get over 100,000 miles, the car's suspension and other similar parts start to show its age.
100k miles is nothing for a car and (non IMS) engine, but I've seen a number of people who need to start refreshing the suspension, motor mounts, etc.
My 01 only has 56k miles, and everything is still pretty tight, but even my ball joints occasionally make a noise. I had an 01 S55 Mercedes, and after 100k miles, numerous items went south. (Ball joints, motor mounts, etc)
Of course, when you've updated the car, a 150k car can feel like a 50k car. My Mercedes was spotless and drove perfectly up to when I sold it at 180k miles.