I am a heavy user, so I clean my grates at least weekly. I just burn the grease and crap off and then take a wire brush to them. About once a month I will take a crumpled piece of foil and scrub the inside top and walls. My grease/water pan gets a build up in it so I have to scoop some of the burnt grease out. I do that on an as needed basis.
This is my smoker.
Team: Pyle's BBQ; Yoder YS640; Good-One "Trail Boss" 60T; Weber Kettle w/rotisserie ring; Big A$$ Rotisserie; Weber OTS; New Braunfels offset smoker.
Saddles BBQ Bistro