I have only had my Saffiano Lux tote for about a month and I have not had any issues with the bag. I am really careful/paranoid about all of my bags, so I tend not to get stuff on them.
I would think that due to the nature of the Saffiano leather, any marks would come out with mild soap and water as tweezer suggests. I wouldn't imagine that the leather needs to be treated in any special way to keep it looking good.
This is one of the many things I like about the Saffiano tote, it appears to be pretty low maintenance and durable!