If you have high cholesterol or high blood pressure (or if you're worried about having it), you may have been tempted by the many at-home cholesterol tests and blood pressure monitors currently on the market. The devices promise quick, accurate results in the privacy of your own home, a boon for busy people who don't like to sit in waiting rooms. But do they actually work? And are they worth the investment? Read on to learn which products are worth the money and which are not.