If something drastic happens, maybe.
I'm a bit ADD with my tank layout, so once every... month or so (I think I may have finally hit a point where I won't do this as crazily - mostly because I've planted my plants in gravel) I take all the decorations and everything out and clean like crazy, while keeping like 30% of the water in the tank. I don't wash anything I take out, either. I just take it out to get it out of the way. Overcleaning bad. Me knows this.
I'm still going to take out what I can take out and do that once a month, though. It's good to vacuum underneath everything somewhat often, but that's about it.