Experienced Time

For his birthday, an astrophysicist of my acquaintance decided to calculate how much experienced time he had lived thus far (because of course he would).  Because when you're, say, 3, the interval between one year and the next is virtually unfathomable--it's a solid third of your life, right?  A birthday is of course a huge deal at that age.  Then by the time you're 5, a year has shortened to only a fifth of your life, and when you're 10 that's only tenth, and so forth.  B...