Most late model leather seats have a vinyl coating on them The exceptions are Ford King Ranch leather and some very high end luxury cars.
Wipe then off with a clean, damp microfiber cloth on a regular basis. Dirty seats wear faster. Keep them out of direct sunlight for extended periods of time.
This is the best stuff I've found to clean and condition finished leather. It will darken non treated leathers though.
How to Clean Leather, A Cleaner, Conditioner, Protector for Leather Only - Leather Cleaner : Leather Cleaning : How to Clean Leather : Leatheronlyproducts.com
Lexol products work great too. But more so for shoes and tack.
Also, jeans wear leather seats on the edges sliding in and out. Get some rock sliders or steps if you don't have them. Try to sit down it and get up out of the seat rather then just sliding out