^^ They're made from a very thick, tough leather (buffalo I think), and I just rubbed them over with dubbin once or twice a year. You don't polish blunnies- that makes you look like the new kid on the block. I have had the soles replaced once. The Thai humidity destroyed several of my other shoes.
I saw some suede, or leatherette sneakers on this thread. Depends where you live I suppose, but I certainly wouldn't recommend them in rural Thailand- except for going out on the town in dry season. Of course my most common footwear in Thailand was thongs.