I would say if there are not issues with parents/police, don't worry too much about the inside of your piece. I don't like to clean the bowl itself too often as I like the hole at the bottom to be small so I have to worry less about sucking ash through. Also I dislike screens. I would say every 30 bowls you pack (this will vary depending on the size of the bowl. If its smaller, you should do it more often, so there is room for actual weed when you go to pack it. Also make sure the hole at the bottom doesn't get too small). Take then resin you remove and store it for when your out of bread, or you connection runs dry. Resin, is arguably "dirtier" smoking, but the thc is more concentrated so, you get more bang for your lung deterioration. Keep in mind, any smoke is bad for you, so I say fuck it, smoke resin. It will help you get through the "hard times" and its a real decent high.