How many hours can a tampon be safely used for at a time? Is #1 greater than or equal to 24?
Menstruation
Tampons are intended for use up to 8 hours at a time.  When left in for longer than 8 hours, tampons pose a dangerous risk for a life threatening condition. 
Regular discharge of blood and tissue from the inner lining of the uterus through the vagina
Are tampons a good 24 hour solution for mentruation?