I've had those leaves in the entire time, well some of them actually longer since I had some in while I was fishless cycling. They're breaking down a little but not overly much. I don't have anything that really rough on them. I actually plan to just leave them in. I do keep an eye on my filter to make sure it doesn't get clogged. Haven't had a problem yet. I didn't clean them either. Just tossed them in and let them sink. My red lizard whiptails seem to love the biofilm on them.