When should moisturizer be applied?

For people with dry skin, especially those with atopic dermatitis (eczema) I recommend moisturizing twice a day at a minimum. After bathing I find it helpful to use a petroleum jelly based lotion. These tend to be clear to off-white or yellow. While they do not add water to the skin they provide an excellent barrier and allow the water from the bath to stay in the skin. At the other end of the day (i.e. in the morning if bathing is at night) I recommend a water-based moisturizer. These tend to be white, and of varying thicknesses. There are many good options, and many are not overly expensive. I recommend getting one that is fragrence-free. Experiment to find the product that is best for you.