The concept of the Day and Night Hydration Lock by ChapStick is simple and clever - moisturize your lips day and night with dual ends customized for each time period. The tricky thing is remembering to apply your chapstick when you go to bed. That said, the day time skin protectant is nice!
Most lip balms and sticks make me chew my lips because the film is so thick I try to remove it subconsciously. This one is moderately light - you are still aware of it but I didn't find myself chewing too terribly. I think this would be great under a lipstick, too.
The night time side I have only used twice and could tell my lips were softer in the AM but I have a hard time remember to apply it each night.
I usually carry my stick in my purse so by the time I am in bed and think about it I don't feel like getting my lazy butt up to go into the living room to grab the stuff. I almost wish these were in separate sticks and then I could leave the night time stick on my night stand by the bed.