it depends on how badly marked up they are.
a good leather repholstery shop can do wonders for seats and you can actually do the work yourself if too.
if they are badly cracked the leather will need to have a filler applied then sanded back colour sprayed and then treated it can literally turn old worn out seat to looking like new.
this runs you through the process here:
Car Interiors Leather Repair & Restoration
the bolsters on my sports seats have the usual scuff marks on them, but last week, literally i purchased some coloured leather balm here:
Leather Re-Colouring Balm
worked it into the bolsters and wear areas, and hell... it's come up amazingly well !
i'm sure you'll get equivalent products in the US of A.. you have literally everything there (and often cheaper too)