Who knows if it's true or what it actually means, but I once heard that the cells in anyone's body become utterly revised or new every twelve years. A complete overhaul. And if that were true, today I would be six years old. Happy birthday!
But as I think about the twelve-year hypothesis, I get confused. It's not as if anyone went to bed one night and then got up in the morning and put on new underwear. It's not a shazzam-you're-completely-different matter. Over a period of 12 years, old parts are replaced here and there. Oil filter, spark plugs, alternator, brakes ... things get changed as one cell runs out of steam and another arises to fill in the gap. So at what point does anything become brand new ... or become old for that matter either.
The matter -- even if it's not true -- throws the whole "new" business into question. What new thing is there that is truly new ... ever? Or not-new either? Things seem to be different even as they are the same. Or the same even as they are different. Does anything ever 'stop' in a way that will satisfy the mind's demand to call things "new?" New job, new friends, new cars, new cell structure, new discovery, new philosophy, new religion, new tooth brush, new sunrise....
I could fit this all into a Buddhist template and prattle on about the 'interconnectedness of all things' or 'dependent co-arising,' but that strikes me as more hindrance than help. When something actually does happen and when it's right in front of your nose or rattling around in your mind's heart, well ... isn't that the important part?
I suppose there are people wise enough not to concern themselves with such things, but I'm not one of them. I'm only 6.
PS. Here's an apposite -- and, I think, hilarious -- clip offered in a comment below: