Wear a thong when you want to avoid a panty line. Thongs are typically worn for the purpose of avoiding a panty line in tight pants, dresses, or skirts. The problem with most underwear is that no matter how thin the material, you can almost always see the outline of the hem through tight bottoms. A thong remedies this situation, as pants are rarely so tight in the front that you see the front outline, but in the back the hem is safely tucked away by your bum.
Thong: Giving you the least amount of coverage, a thong has just a strip of fabric in the back to prevent panty lines from showing through clothes. According to Dr. Dweck, they're totally safe as long as they're not too tight. "The right thong with a cotton crotch and non-chafing 'G-string' that fits well is not a problem for those who prefer them," she advises.
Avoid wearing thongs every day. For the same reason that you should change your thong on a regular basis, you should avoid wearing your thong every day. Bacteria can easily travel up the fabric of the thong, which means wearing one every day can make you more prone to infections. Try wearing thongs only during the day or times when they are a needed fashion piece. Wear full-coverage panties at night, when you work out, and when you are wearing heavy jeans or other bottoms which won’t show your panty line.