In general, people lose 1 to 3 eyelashes per day, says ForAnyWomen.com. This is a normal process and often goes unnoticed as eyelashes are very small.
It takes around 2 months for eyelashes to grow, after which they last approximately 3 months, according to WebMD. Eyelashes are constantly growing at different rates; this prevents large patches from being bald at one time.
Eyelashes are crucial to the health of eyes, and are essential in preventing foreign bodies from entering the eyes. The nerves in eyelashes sense when they are being touched. This instigates the blink reflex, an important reflex which can protect the eye from being damaged.