We all know that time seems to speed up as we grow older, but a columnist from The Guardian has dug up some interesting research illustrating just how much it speeds up:

According to studies at the University of Cincinnati in the 70s, this effect is so pronounced that if you're 20 today, you're already halfway through life, in terms of your subjective experience of how time passes, even if you live until you're 80. And if you're 40 - again, assuming you live to 80 - your life is 71% over. Basically, if you're older than about 30, you're almost dead.

Why does this happen? The most convincing explanation I've seen has to do with how our brains process information. Our subjective experience of time tends to slow down when our brains have to learn new information and create new memories. Children are constantly experiencing unique situations and adapting, from how to ride a bicycle to basic algebra. By the time we're adults, however, we become creatures of habit and our brains have developed "shortcuts" for most of these processes. Whereas riding a bike once required a great deal of concentration, it has now become a routine that doesn't require much mental capacity at all.

So the time-slowing secret? Break your routine; seek newness; learn, Burkeman says. People who go on adventurous trips, for example, report longer-seeming holidays than those who choose the regularity and inactivity of a week on a beach.

In a nutshell: Stop taking shortcuts.