Sig1855

I have been using Zymol products for 20 years. The leather in my 2001 Infiniti (owned since new) has some creases but overall looks like a car that's a couple years old, not 18. I lather it in the conditioner every 3-4 months, and use the cleaner as needed. Granted, our Lexuses are a little different given the polyurethane, but I use the same method.

2GR

After trying several leather conditioner/cleaners (e.g. Lexol, Meguairs, etc), Chemical Guys is the only one I've used that doesn't really leave a sticky residue.