What they are: Blood glucose monitors, or meters, are devices the size of a cell phone or smaller used to monitor your blood glucose levels. They are typically used with lancets, for drawing blood, and test strips, on which you place the blood sample to get a reading.

Why to buy: Keeping track of your blood sugar is essential for staying healthy and avoiding diabetes complications. Look for kits that can hold your monitor, test strips, and lancets all in one place for easy access. Some glucose monitors provide more information than just your blood glucose level. The more advanced meters offer graphs and the ability to save results, and some allow you to download results to your computer.

Things to consider: Some meters allow you to use blood from places other than your fingertip (often called "alternate site testing"), and some have a large display screen or spoken instructions for people with visual impairments. Some meters require smaller amounts of blood to achieve an accurate reading, resulting in a less painful finger prick. Look at the manufacturer instructions to determine whether the blood glucose meter needs regular cleaning or other maintenance. Also note the type of batteries required and their cost. Testing supplies are sometimes covered by third party payers—make sure to see which brands your insurance covers.

What they are: Lancets are disposable pins used to prick the finger in order to draw blood samples for use with glucose test strips. The gauge of the lancet refers to the width of the metal point. And while it may seem backwards, the higher the number, the smaller the lancet. For safety and accuracy, lancets should be applied with a lancing device (sometimes called a pen), which is a reusable instrument with a spring mechanism to help the lancet quickly and painlessly puncture the finger (or alternative site) for the blood sample.

Why to buy: Lancing devices allow you to adjust how deep the lancet penetrates, depending on the sensitivity and thickness of your skin. For safety, most lancing devices conceal the needle before and after use. Some make the lancet inoperable once it has been used, which is an extra safety feature to prevent painful reuse of the lancet, or accidental use by a child.

Things to consider: Usually a higher-gauge lancet is less painful to use, but keep in mind it may be harder to get an adequate blood sample. It is imperative for health and safety reasons that lancets be used only once. Remember that lancets are an ongoing expense, so be sure to stock up.