I've had leather interiors for the past 16 years -- all of them in Texas. The best defense against premature wear I've found is all about keeping the hides clean and supple: Pre-summer and pre-winter, clean with saddle-soap and dry it off, then slather with pure mink oil, allow it to absorb for an hour or so (depending on cabin temp), then wipe off any excess with a cotton towel. Those who don't like mink oil's initial "gamey" odor may want to use another leather restorative, like Lexol.
NEVER use anything with silicone.
