Hydration

Hydration is water going into the skin, and that comes from a toner, an essence or a humectant serum. Moisturizing is stopping that water leaving again, which is the job of a cream with its ceramides, fatty acids and squalane. Skin that feels tight right after cleansing wants more of the first. Skin that looks rough by evening wants more of the second.

Usually yes. Oily skin that feels tight by mid morning and looks dull rather than glossy is often short of water, not oil, and stripping it further tends to make the shine worse. Gel creams, watery toners and light essences suit it better than a balm or a heavy cream. Keep the textures thin and let each layer sink in.

One is enough for most skin for most of the year. The seven skin method, several thin layers of toner pressed in one after another, is worth doing in a cold week or after a flight, when skin takes each one straight in. Press each layer in with your palms while skin is still damp rather than rubbing, and if a layer is still sitting on the surface after a minute, you have added one too many.