I don't know if this is technical or not, but....
On a car like a 2000 Toyota Camry Solara, with leather seats, how much of the seats are leather? Just the tops of the seats and fronts of the backs? Just the front seats, not the rear seats?
It seems that different products are best to preserver leather from vinyl, and the seats get a lot of sunlight and even dirt and once in a while rain** since it's a convertible.
**I keep a rag and a towel in the car to wipe up the rain.