Having worked in Retail Auto Parts for most of my adult life, I can tell you that an alarming number of grown men and women couldn't....
Tell you what year their car is
What size engine is it
How many cylinders it has
How many miles its been since the last oil change
and my favorite
Where the hood release is
Much less how to change anything. I'd still be damned if anyone is going to change my wipers or battery just because there's a sign on the window of the building. It's my car! They are not touching it.
I don't know where all this knowledge disappeared to, I'm 44, I've known all of this and more my entire life. Like many here I can tell you how many miles are on my tires of each of my vehicles. My father taught me, "take care of your car, and it will take care of you" most of my good friends are car guys and gals to some degree. I know a few folks that I love dearly and pick on them every time I "help" them with their car. I'd guess the early to mid eighties, the computer years, is when people started walking away from cars, and common knowledge stuff as well. Although it should be said, I don't remember the last time I had to change a tire on the side of the road.