Yea whenever it starts to look like it may dry his skin out I would put more time in between the next time you give him a bath. Also it would probably be a good idea to use an oatmeal conditioner for dogs to really condition and soothe the skin...it might help keep from drying his skin out. I bathe my baby once a week to a week and a half...just depending on when I have time. I havent ever had a problem with his skin drying out except one time when I didnt use a conditioner on him. Since I got him an Oatmeal Conditioner...it hasnt been a problem.
Good Luck!!