Check this list out from Good Housekeeping. I know I scrub my sink on a regular basis, especially after preparing and cooking meals. Label me guilty of keeping the shower scrubbie around for too long though! My motto, use it till it wears out, but I may have to adopt this practice of discarding it after a month. It also helps that they are relatively inexpensive. Good Housekeeping always has great ideas. Check the link below for some other great tips!