I don't vacuum my planted tanks at all. Water change when the nitrates hit 5ppm or once a month, whichever comes first. Once I get enough plant growth, my nitrates barely rise above 0ppm and I just go to a once a month water change permanently. I also have snails, shrimp, and other critters helping to keep the substrate clean. I prefer the natural approach to a synthetic environment with sterile substrate, dosing ferts, high light, etc.