Head Lice live from three weeks to six weeks, depending on temperature and humidity. During its lifetime, a female can lay up to 100 eggs at a rate of about 6-7 a day. Of those eggs, only the ones that have been fertilized will hatch.
Head Lice must feed on human blood every day in order to survive. Once they are dislodged from their host, they will die in about 48 to 55 hours at 75 degrees F. The nits can survive for 4-10 days off of a host, but once hatched they must feed on a human host within 24 hours, or they will die.
Remember it is important to also treat your environment thoroughly with the All Stop Professional Steamer and DE (Diatomaceous Earth) if you contract Head Lice.