If it's surface cracking, no big deal. I would go ahead and spring for a small tin of Proofide (the Brooks stuff). If the cracking is along the edge (i.e., notches in the edge of the leather) it's probably just a matter of time until the saddle splits. I have a 45 year old B72 that split like that so I had to replace it.
__________________
I stop for people / whose right of way I honor / but not for no one.
Originally Posted by
bragi 
"However, it's never a good idea to overgeneralize."