16. You don’t use a meat thermometer.

Result: Your roast chicken, leg of lamb, or beef tenderloin turns out over- or undercooked.

Small and inexpensive, the meat thermometer is one of the most valuable kitchen tools you can own. Using one is the surefire way to achieve a perfect roast chicken or beautiful medium-rare lamb roast, because temperatures don’t lie and appearances can deceive.

We love digital probe thermometers, which allow you to set the device to the desired temperature. A heat-proof wire leads to an external digital unit that sits outside the oven and beeps when the meat is ready. This eliminates the frequent opening and closing of the oven door to check the temp―during which you lose valuable heat―and that speeds the cooking.