I like to take everything out after each cook and clean it up. Vacuum out the firebox (after it's cooled, of course), pull the grates and let them soak in hot soapy water before cleaning and get all the grease out of the bottom of the cook chamber. That can be a nasty place for harmful goo to grow if you don't clean it out shortly after you've cooked, and you may be flirting with some good ol' gastro issues if you leave it in there for multiple cooks: especially if you're talking days or weeks between cooks. Recommend putting some type of drain valve in the lowest point of the cook chamber--it will make that part of your clean up much easier when you can simply open a valve and collect all the drippings, versus trying to get that stuff out of the top.