I spent about $50 in leather conditioners before I realized the proper procedure for rejuvenating hard leather seats. I know it sounds weird, but break out some 220 grit sandpaper and sand the seats lightly to open up
some of the pores in the leather. Next, apply some Leatherique or Colorplus leather soffener (I use Colorplus) and allow the seats to soak up the soffener. This works best in the hot sun which will speed up the absorption process.