An infection, injury or plucking disaster can leave you with a dearth of eyelashes. The fringes will grow back, but slowly. If subjected to repeated pluckings, though, eyelashes may give up like other hair follicles and become resistant to growth.

Eyelashes are more than frames for the windows to your soul; they protect your eyes from dust, sweat and small objects. Each eyelid has three to five layers of eyelashes — with the upper having between 90 to 150 lashes total, and the lower between 70 and 80. Expect your lashes to grow to almost 1/2 an inch in length. The eyelid’s reflexes cause you to blink in the face of danger, allowing the lashes to do their cleansing work.

Any hair on the human body begins with a follicle that lies below the skin’s surface. A hair begins in the anagen phase, when it is actively growing. This length of this stage varies depending on where the hair is on the body, but for eyebrows, it lasts approximately 45 days. Once the hair is fully grown, it enters the catagen (or transition) phase, during which it does not grow and the follicle shrinks. The final phase is the telogen, or resting, phase. This is when the hair detaches from the papilla, floats up the shaft, and falls out, sending the follicle back to the anagen stage.

You shed eyelashes naturally, but these have replacements at the ready so your noticeable gaps aren’t obvious. A plucked eyelash, however, may take as long as two to four months to regrow. Even if you don’t mean to pluck out an eyelash — such as lashes that fall out when aggressively lash curling or applying mascara — you can do damage. If you repeatedly pull out eyelashes, you risk damage to the follicle and potential stunting or halting of eyelash growth.

Sudden loss of eyelashes can result from a serious eye infection or a condition such as alopecia areata, or hypothyroidism. If you find your eyelashes falling out at an alarming rate or resisting regrowth after several months, seek evaluation from a dermatologist or ophthalmologist.

If you’re aesthetically worried about thinning eyelashes, you can try an eyelash growth serum. These contain proteins, other products and extenders that may improve the appearance of your lashes, but their effectiveness can vary.

Wash off makeup every night before bed, especially clumped-on mascara. Use an eyelash curler with care, and only for about 20 seconds a side. Avoid using old makeup that could cause infection — an enemy of healthy lashes. A healthy diet also helps keep all your hair in tip-top shape, including your lashes. Include omega-3 fatty acids and plenty of protein to support hair health.