There are a great number of leather conditioners/cleaners out there and I believe everyone has their favorite. Go with a name brand and as has already been said use it regularly. It will keep the leather not only clean but also keep it and the stitching from drying out, cracking and less likely to stain. If you don't already and you have a lot of hot sunny days, get one of those reflectors that you put in your windshield. The sun can be bad on cloth interiors for fading but it can be murder on leather.
I use Lexol-ph Leather Cleaner and then treat with a German product called Super VII Leather Balsam. I'm very satisfied with Super VII as it is essentially an emulsified beeswax product.
Normally beeswax would cake on the leather surface but this product absorbs completely into the leather and is does not leave a greasy of slippery surface. Obviously the advantages to a wax are waterproofness and no deformation of the leather due to streatching.
I purchased it at my local Auto Show but you might try a web search to locate.
BTW the Super VII makes the leather look richer and of a higher quality. Super VII also absorbs into the plastic surfaces leaveing a nice, non-slick. luster.