There is definitely something about hitting your 50's, at least for me that was the case.  Suddenly I became more focussed on the whole business of ageing or more importantly not ageing.  I don't mean worrying about wrinkles or the sudden appearance of grey hair (grrrrrrr).  I mean how to age well  in a 'be disease free, able to leap around full of energy embracing life 100% AND with a full set of marbles'.....sort of way.