When I was in college, I took a physiology class (1995 maybe? it's so long ago that I gt confused!) Actually, it wasn't that long ago - definitely not earlier than 1995 - but no one I knew had cell phones. The first person I knew who got a cell phone was my friend who moved away from the immediate area when he graduated and got this horrible analog phone... but it was better than what anyone else had, which was nothing.
Anyway, I was in this physiology class, and someone's cell phone ring. It was the first time I had ever heard a cell phone ring during class and the professor just pointed toward the door and said, "OUT!" It was a 500+ person class and everyone watched as the disgraced student left.
Not even 15 years ago.
Last week, as I was subbing in kindergarten, two out of the 15 kids had cell phones. Two kids might not seem like many, but remember, these kids are 5 years old. They don't all know how to write their names yet. They don't know all the numbers to 10 or all the letters of the alphabet. But two of them have cell phones. Incidentally, the way I found out is that the cell phones kept falling out of their pockets. It turns out that kindergarten pockets are too small to fit cell phones.