The answer to this differs from one diabetes patient to another. Each diabetic patient has different requirements. However, note that you can't make a decision on your own about how often you need to check your blood sugar levels. Hence, you need to keep in touch with your doctor regularly as they provide proper guidance to control blood sugar. As a matter of fact, experts highly recommend checking blood sugar levels and taking the readings twice a day. And not just any time during the day, but only pre-lunch and post-lunch timings. However, if the problem is severe and if your diabetes reading is always high, then you need to test 3-4 times a day.