Like the air we breathe and the water we drink, underwear is a part of life  so ubiquitous that it often goes unnoticed. Don't let another year pass being unclear about your underpinnings — especially considering 99 percent of you are wearing them right now. (And if not, well, maybe you should be.)
We're exploring the wide yet sometimes very, very thin world of panties and breaking down the seven most common styles — sorry, no crotchless or C cups (we beg you not to Google Image search that) here.
Modeled after men’s briefs, they take on a more rectangular shape than most panties. Similar to the hipster, the key difference is that they have a lower-cut leg. In fact, some styles' legs extend a short way down the thigh.
When to wear them: When fitted properly and made from the right fabric, boy shorts can actually serve the same function as a thong in being worn under formfitting clothes without visible panty lines. Longer cotton boy shorts, however, can even be worn as loungewear or pajamas.
Warner's No Pinching Boy Shorts  ($9, originally $12)
Pact Women's Basket Weave Boy Short  ($12, originally $17)
Forever 21 Seamless Boy Shorts  ($5)
Target Micro With Lace Boy Shorts  ($4, originally $5)
Commonly identified by the colloquial term "granny panties," this undergarment provides full coverage and a high waistband. Sure, it's not the most attractive style of underwear, but it's certainly the most comfortable.
When to wear them: Unfortunately, the up-to-the-navel waist makes these visible in low-rise jeans and trousers, so limit them to your high-waisted pants or for, you know, that time of the month.
Jockey Elance Three-Pack 100% Cotton Underwear Briefs  ($17)
Victoria's Secret All-Over Lace Brief Panty  ($12-$13)
Simone Perele: Folies Control Briefs  ($70)
American Apparel Unisex Baby Rib Brief  ($14)
Often referred to as high-cut panties, these gained a resurgence in the 1980s, thanks to Jane Fonda's exercise videos. They have the same high waist as the classic brief, but it features high-cut leg holes that rise just above the widest part of the thigh, which is often better for circulation.
When to wear them: If you are Miley Cyrus . Or if you want the coverage of a brief but find the elastic band around the leg uncomfortable.
Bali Lacy Skamp Hikini  ($7, originally $11)
Vanity Fair Illumination Hi-Cut Brief  ($8, originally $10)
Hanky Panky Signature Lace French Brief  ($27)
Spanx But Naked High-Leg Brief  ($10, originally $19)
Not meant to be worn by hipsters alone, this style — also called hip huggers — got its name because the waistband sits on the hips, a full two inches below the waist. They also feature low-cut leg holes.
When to wear them: These still provide full coverage but are perfect for low-rise jeans and pants.
TC Sporty Hipster Briefs  ($18)
DKNY Delicate Essentials Hipster Panty  ($12)
Evollove Five Kisses Contour Brazilian Brief  ($19, originally $35)
Hanky Panky Signature Lace Cheeky Hipster  ($32)
This pair of underwear is modeled after, naturally, women’s bikini bottoms. The waistband sits a full three inches below the natural waist and has very high-cut leg holes. They also come in string bikini form, in which the leg holes are constructed with a thin string of fabric. The front and back of the string bikini look like triangles.
When to wear them: Because they provide little coverage, they are less visible underneath clothes and thus can be worn under most anything.
Calvin Klein Crochet Bikini Underwear  ($15, originally $24)
Stella McCartney Magnolia Shrugging Lace Bikini  ($50)
Elle Macpherson Intimates Embroidered Bikini  ($30)
Gap Skinny Bikini  ($11)
This is the style most often sought when needing an undergarment for formfitting clothing, like tight skirts or dresses, because it provides no coverage on the butt — and thus no panty lines. Like the bikini, it sits three inches below the waist. Often, the sides are meant to rest right at or above the hip bone.
When to wear them: Whenever you're in the mood to twerk to some Sisqó. Or when you're rocking a body-con dress or tight pants.
Target Women's Modal Thong Three-Pack  ($11)
Victoria's Secret Lacie Thong Panty  ($13-$15)
L'Agent by Agent Provocateur Leonara Thong  ($44)
Gap Sexy Invisibles Thong  ($13)
There's little to the G-string panty. Like the thong, there's no rear coverage, and this style also provides little up front, where it forms a T shape of fabric. The front and back pieces attach directly to the waistband.
When to wear them: To your next hot date? Because thongs and even boy shorts often provide a seamless look underneath clothes, it's rarely necessary to require a G-string.
Cosabella Never Say Never Skimpie G-String  ($19)
Mimi Holliday Jam Roly Poly Thong  ($62)
Betsey Johnson Stretch Knit G-String  ($12)
American Apparel Sheer Jersey T-Back Thong  ($8)