Time is a pretty underrated aspect of any beauty treatment. The effects of using more of an active ingredient, for instance, is quite different from that of using less but allowing it more time to work. Sleeping packs and masks fall under this category. Here are a few things you should know about sleeping packs: 1. They have an incredible variety. Different packs do different things. For instance, some are better suited for skin lightening while others are formulated specifically for an anti-aging effect. Be sure to choose one that actually works the way you need it to. 2. They can get messy. While many are absorbed into your skin quite quickly, others might leave residue for at least a few hours. Few people can sleep rigidly on their backs, which results in sleeping packs creating a mess as someone tosses and turns in their sleep. Using a neck pillow and a clean, sacrificial pillowcase can do wonders to mitigate this issue. You can also put a towel on your pillow or simply schedule your mask the night before you do the laundry. 3.) They’re best used once or twice a week. Sleep packs can be quite potent, especially given the long amount of time they can sit on your face. Try using a regular night cream or serum on other nights of the week instead.