"I can always tell when we're shifting from summer to fall months based on my hair. Right around the middle of September, I feel my ends getting particularly dry and notice way more flyaways. Thanks to this Olaplex No. 7 Bonding Oil ($28), though, I've been able to maintain the texture of my hair. I put a little bit on before I apply any heat to my hair and then a little extra just to my ends afterward, and the results are incredible." — Kelsey Kennick, senior manager, Commerce