2. Allow to dry. To prevent bacteria growth, you'll want to make sure you're mop dries out before storing. Start by wringing the mop out as completely as you can. Allow it to dry completely by placing the mop head outside on a clothes line, or standing the mop with the mop head up in a bathtub or shower area. The temptation is just to hang the mop up and hope it dries. Taking a few steps to make sure the mop head is fully dry will save a lot of trouble later.
3. Store properly. Store your mop in a cool dry place. Try hanging the mop so that the mop head isn't brushing against the floor. If you've allowed the mop to dry thoroughly, the mop should be fine until the next use.
4. Replace when needed. Replace the mop head as needed to keep it from becoming a cleaning hazard. Mop heads may last for awhile, but eventually will show signs of needing to be replaced. Instead of trying to stretch out its usefulness, replace the mop head and keep your floors clean.