5 For Best Results You Should Stick to One Product Line. 為了達到最佳效果，你應堅持使用同一系列的產品。

Another fallacy promoted by sales reps. Certainly, you may love how all the products work

together but using products from different lines won't kill you. Every cosmetics line has

products you should avoid because they contain irritating ingredients, inadequate amounts

of sunscreen, or moisturisers that over-saturate the skin. Experiment and find the products that are right for you.
又是一個銷售代表宣揚的謬論。當然了，你可能喜歡整套產品一起使用的效果，但使用不同系列的產品不會害死你。每個化妝品系列都擁有你該避免使用的產品，因為它們含有刺激性成分、含量不足的防曬成分或是過度滋潤肌膚的潤膚劑。要在適用后找出適合自己的產品。