When you have dry skin , you're more likely to be fully committed to your skin-care routine in January than any possible New Year's resolution. From heavy moisturisers to hyaluronic acid serums and even desk humidifiers, 'tis the season to stock up on anything and everything that might provide you with a much-needed H2O boost. So why give your thirsty skin all that TLC only to then layer on a foundation that will leave you drier than you were in the first place?