not much if at all. you have to get this special leather treatment stuff and you first clean the leather, then you apply the stuff and wait 12hrs. the problem is, it has to be fucking hot in order for the stuff to work. some where around 120-150f. your best bet is pick a hot day and hopefully have time to do the cleaning before the day and hope for the best.

it's a long and tedious process but i've seen cracked leather look brand new after that (the guy also dyed the leather again) to get rid of the cracks there is no other way. no conditioner will make any sort of visible difference. remember conditioner is to keep the leather in the "good condition" if the leather if cracked, you have to repair it.