We all know we're supposed to do that, let's say, 3-4 times a year, because an old toothbrush harbors bacteria and all that good stuff. But from another point, this is also an issue of renewal.

Our ancestors had their own ways to make sure their lives were cyclical and always renewed, but we seem to have forgotten everything, using ancient ceremonies as excuses for shopping (at least in the more recent past. Now holidays are excuses for window-shopping). Fair enough. Things change.

But we can make our own small renewals. We can make sure every day starts anew by making sure the kitchen sink is empty at night. We can make sure every week is a new beginning by doing something special at the end of the weekend.

And we can get a new toothbrush every three months, so when we feel the fresh bristles we know we are renewed.