I used to use Zaino religiously, but then I found this:
http://www.amazon.com/Leather-Condit...s=leather+nova
By far the best leather treatment I've ever used. It does darken the Nappa a bit (I have mocha), but after a few days it lightens back up. Only need to apply it 2-3 times/year whereas I was using Zaino monthly. One caveat... I do not use it on the leather dash. For that, I still use zaino. But since it doesn't see any action on it, I only apply once every 3 months.