motov8 saidEverything fades.
It's called entropy.
Entropy is that nature tends from order to disorder in isolated systems.
That's true for stochastic systems, but ageing is genetic, i.e. programmed into us. In people who live to 100 and beyond, it's found that a certain set of genes seems to be key. The fraying of telomeres (the ends of chromosomes) also contributes to ageing, whilst things like balding are the result of male hormones causing hair follicles to atrophy (an evolutionary signal to females that the male has reached maturity).
It is probably less a case of entropy and more a case of obsolescence. We evolve by dying out and being replaced by the next generation of product.
Diet and exercise are about the only things you can work on to mitigate this predisposition.
Anyway, in answer to the original question: Ageing tends to make a person more stable and reliable, because they realise they don't have as much time ahead as they've wasted in the past chasing after men and women and work reduces their free time. Women seem to prefer maturer men, whilst men prefer younger men and women, because they find them better looking.