these are just some examples i found on my own bags.
this is a leather from season 3 year '02 flat brass caramel classique. the leather's thicker and smooshier than my season 2 year '02.
this is a leather from a red first '03. it's smooth, but not as smooth as an '02
the seafoam purse comes from spring/summer '04, the leather so smooth and not as pebbly as the orange '04.
an orange from spring/summer '04. although seems cracker than the pistachio, but the leather is as thick, although i found it smoother and smooshier.
the pistachio comes from fall/winter '04, the leather is also smooth and thicker than my '02 or '03
eggplant from fall/winter '04 too. the leather is very soft but not as smooshy as the orange.
indigo pre-spring '05, after years of using, this bag is as smooshy as my eggplant '04 leather... very yummy
magenta pre-fall '05, the leather is not as soft as the '04 or earlier, but what i love is the glossy texture that brings out the color of this magnificent bag.