I am looking at my driver sit leather and I see it significantly wrinkled - not cracked yet, but... The car is 2004 with 48000 miles on it - how long before I should expect the leather sits to crack? What is the best way to extend their life expectancy? BTW - are the sits made from *real* leather? I have my doubts looking at the map pocket behind the sit, which looks like just black vinyl with white foam or cloth undercoating...