The lifespan of our hair systems is determined by how well they are taken care of. Usually, lifespan is from 6 months to several years depending on how often they are worn and how well they are taken care of and what chemical treatment it had to undergo when being made.
As a rule of thumb hair in virgin color (which is „natural black“) will hold much better than in light or highlighted color. Also, straight hair is always more moisturized than wavy hair or curly. So if you order light color or highlighted hair in a curly texture, only very highest grade pure hair has to be used; however, such chemical process would definitely have a negative impact on quality of hair and so shortens its lifespan.