Modern kitchen faucets should last at least 15 to 20 years with proper maintenance. Pull-down faucets are more susceptible to wear and tear than conventional taps, due to their additional components such as hoses. Technology is always improving, however, and a pull-down faucet from a respected brand should still last you at least a decade. Check the warranty, as it is usually a good indicator of how much faith brands have in their products.