Keeping the glass clean isn't fun, but a clean widow IS fun. If you don't keep up with it nearly every smoke, it takes a fair bit of elbow grease to get the thick buildup to budge in my experience. I clean the grates if i'm putting stuff directly on them, but lately i've been using big baskets that i can slide in and out easier, so now i only clean the grates if they're really bad. So far I have not cleaned the walls or the back.
ANT0407 gives a good reminder to clean the temp probe. buildup on there would impact accuracy. i gotta do that before my next round!