How long your eyelash extensions last depends largely on how well you care for them. With proper care, your lash extensions will look great for three to four weeks. (For tips on after-care, click to the next slide.)

However, even the best lash extensions don't last forever, and you'll see them fall out with your natural lashes; losing one or two every day is normal. Your lash extensions may cling on for weeks or months, but they'll probably start to look patchy after four or five weeks. To keep your lash extensions looking full and even, get touch-ups every two to four weeks.

Lash extension maintenance can be a bit tedious, but proper care is essential to making your investment last. After-care instructions may vary depending on your technician, extension material and extension brand, but most experts agree on these guidelines:

1. Steer clear of greasy products, which break down lash extension glue. "Keep oils, lotions, and creams away from the eye area," says Terrill. "Makeup remover must be oil-free and water-based."

2. Don't use cotton pads or swabs for eye makeup removal.The cotton fibers can get caught on lash extensions. Terrill suggests using disposable makeup sponges.

3. Avoid wetting your lash extensions for 24 to 48 hours after application. Eyelash extensions can and should get wet, but the glue usually needs a day or two to set, depending on manufacturer's instructions.

4. Keep them clean. Full disclosure: In five years of wearing extensions, I never washed them with anything but water. However, many lash extension experts recommend washing them with a gentle, oil-free cleanser. I tried and liked Xtreme Lashes by Jo Mousselli Eye Makeup Remover & Facial Cleanser, $15, at Terrill's recommendation.

5. Avoid unnecessary pressure. That includes rubbing with a towel or smushing your face in a pillow -- side sleepers, take note.

6. Brush them daily. Lash extensions get tangled and tweaked, so use a spoolie to fluff and comb them in the morning. 7. Minimize time spent in steam, chlorinated water or saltwater. Shower with your bathroom door open and skip the steam room. If you love to swim, wear goggles or rinse your lashes with fresh water afterward.

TBH, it's been a little while since I got my last set of extensions. In my old hometown, extension fills cost me $100 every four weeks, which was a little embarrassing when I compared it what I was contributing to my 401(k) every month. I was excited to try them again -- for research purposes, of course.

Before my service, Terrill asked me to fill out a release form and some paperwork, the kind you've probably done if you've ever had a facial: lifestyle habits, skin-care routine, allergies -- you know the drill. Then, we discussed the lash look I wanted to achieve. I told her I was interested in a natural look; I requested extensions a little longer than my natural lashes, but fuller and slightly curlier, with an overall rounded shape. ('Cat-eye' lashes, which are heavier at the outer corners, make my eyes look droopy.)

After that, Terrill got to work. I lay down in the incredibly cozy chair while Terrill carefully taped over my lower lashes with paper tape. (Pads or tape keep the lower lash line from getting sticky with lash extension glue.) With my eyes closed, Terrill applied a variety of Xtreme Lashes extensions -- 0.15 millimeters in width and 8 to 11 millimeters long -- dipping each one in adhesive before painstakingly positioning it on top of my natural lashes. In a little less than two hours, Terrill applied more than 100 lash extensions to each of my eyes. When she was done with the application, she spent a few minutes drying my extensions with a small handheld fan before sending me on my way.

As soon as I opened my eyes and looked in the mirror, I remembered what I love about lash extensions. Just when I thought I was bored to death of my face, it was suddenly new again. My eyes looked bigger, brighter and younger; my features appeared more proportional. I couldn't stop looking at myself in the mirror. My boyfriend was even more entranced with my new look than I was. For a full day, he seemed to get lost in my eyes, whispering things like, "Your eyelashes look amazing in this light."

Probably the best part about my lash extensions is how much time they shave off my morning routine. Without lash extensions, I wore mascara, liquid liner, eye primer and, occasionally, eye shadow; I was always the last person at the brunch table. Now, my eye makeup regimen consists of neutral eye shadow or nothing at all, and I feel just as confident walking out the door.

Lash extensions may cost a wad of cash, but if you're like me, they make you feel like a million bucks. With my retirement and savings accounts in a much happier place, I've given up resisting my beauty obsession. My next appointment is in exactly three weeks.