I think it's so important to wash your face before going to bed, to get all the grime and pollution of the day, as well as the makeup off your skin, because left on the skin, they can clog the pores, and also they can become irritating to the skin. So it's the most important time to wash.
If you were out a little too late and you are just really tired that night, what you can do is get a cleansing cloth. There are some really great pre-moistened cloths that you can leave at your bedside, that don't need to be rinsed off, and for those special nights, you can use that to get as much makeup off as possible.
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