So what type of hair do the pros use? "The hair extensions themselves will vary depending on if you want synthetic, non-Remy [human hair], or Remy human hair," Redway says. "I always recommend human hair. Although it is more expensive than synthetic hair, I find it to be a better investment. Human hair appears the most natural and can be heat-styled as if it were your own hair."

However, Redway notes that not all human hair is created equal. Non-Remy hair is "low-quality human hair [that] may cause tangling and shedding," while Remy hair is "high-quality human hair, usually from one source, minimizing the chances of the hair becoming tangled."

Virgin-cuticle hair is her top pick. "This is the highest grade of hair," she says. "This hair has not been chemically treated, color-treated, or bleached in any way. Virgin hair is the most expensive type of hair to get."