After 3 months: Sanitize the sponge or replace. If you see mold or bacteria growth, do not use the sponge. Some users have boiled it in water to sterilize it, or saturated it in water and microwaved for 20 seconds to sterilize. If you continue to squeeze and hang it to fully dry between uses, it could last for up to 6 months.
If it smells funny, becomes discolored, or looks off, throw it away and do not continue using. It is a natural product and can grow mold or bacteria if not properly handled.
Storage: After each use, rinse out the sponge and gently press between palms to remove excess water. Hang up to dry between uses, with the included string hanger. Never wring out the sponge as this might damage or alter its shape. Replace after 3 to 6 months.