What made you realize that yes, you are getting old(er) now?

No matter what your age is, every now and then we suddenly realize that we get older.
This realization can consist of seeing that the magazine that you were a subscriber of when you were sixteen has had its 5th lay-out change since then.
Or you were around when Volkswagen launched its Golf (Rabbit in the USA) mark I (the current is Golf VI).
I realized my aging today when i heard on the radio that the son of the drummer of a band that was popular in my teens, now himself has a number 10 hit.
It happens to you, these things?
What are they?