A sew-in hairstyle, also known as a weave or sew-in weave, is a popular hair extension technique where additional hair wefts are sewn onto braided natural hair to create length, volume, and/or different styles. Sew-in hairstyles can last for several weeks to a few months, depending on the quality of the extensions, how well they are maintained, and the rate of natural hair growth. Regular maintenance appointments may be required to adjust the sew-in as the natural hair grows and to ensure the longevity of the style.