I do a partial water change and gravel vac mine about once a week. Clean glass (front only) as needed, usually every 2-3 weeks or so. Same with filter media, change out as needed, you can usually tell by looking. I also have live plants in nearly all my freshwater tanks, didiplis, anacharis, duckweed, etc (all floating plants) that need thinned out occasionally to let light through for the java moss, java fern, etc. growing below. I look on this as "nitrate reduction" in addition to my regular water changes.