I have been using your Repel Shampoo and conditioner on my three children for at least 5 years. When ever we stop using it…one of my kids will pick up lice for sure. My 5th grader uses your daily conditioner daily, he recently spent a few days on a sleep over (without the spray) and 7 days later I found nits in his hair but no live lice. I think the spray really repelled the egg laying female. I swear by your products. They work better than ANY toxic chemical treatment!