Yes, it is very important to carry out regular blood tests as you will not know whether your blood glucose levels are under control or not. With mild hyperglycaemis (blood glucose between 180-222-0 or so) you will not have any symptoms but these high levels of glucose will keep causing damage to your organs such as eyes, kidneys, heart and nerves.
You must get your HbA1C once in three months and keep it under 7%. Blood glucose fasting and PP at least once a month with target values of 90-120 and <180 mg respectively. Also get your kidney functions, lipid profile and fundus examination at least once in a year. It is important to keep the glucose and HbA1C levels under target. It is also important to do these tests regularly to modify the treatment.