There are several major reasons you may want to get blood tests more often than that: You’re experiencing unusual, persistent symptoms. These could include anything from fatigue to abnormal weight gain to new pain. You want to optimize your health. Knowing levels of various blood components, such as HDL and LDL cholesterol, can allow you to tweak your diet or fitness plan to minimize unhealthy habits (that you may not even realize are unhealthy). This can also maximize the nutrients you put in your body and more. You want to reduce your risk of disease or complications. Regular blood tests can catch the warning signs of almost any disease early. Many heart, lung, and kidney conditions can be diagnosed using blood tests.