Spot clean poop as needed (you can even dig a little hole and drop some poop down in there to add nutrients deeper in the soil). Wipe glass down with dechlorinated water as needed. The ABG mix can last for a couple years before it needs to be replaced if properly cared for.
Watch the drainage layer and siphon off excess water as needed. You don't want that water to swamp out the soil or you will be replacing the soil much much sooner. You will know if this happens because your tank will smell like rotten eggs.