I don't, I don't see the need.... BUT I do use a good leather conditioner on all my smooth leather, which helps keep the water and dirt off and conditions the leather. But as stated the Alegria shoes are made with special finishes and the pair I just bought won't absorb the conditioner so I won't be doing anything to them.
BTW, if you develop a squeek in your Alegrias, take out the inner sole and shake some foot powder or talcum (gently) inside and replace your inner sole. It usually will get rid of the squeek for awhile. If you still have the squeek, apply again.... 
*~"Never eat more than you can lift......" Miss Piggy~*