With every injection you have to rotate the insulin injection site. The next site should be at a minimum two finger width away from the previous injection site.
You may rotate clockwise or anticlockwise around your abdomen.
Between the abdomen, thigh and arms also, keep a rotation between the areas.
This helps to keep the injection site healthy, also optimizes the absorption of insulin and reduces the risk of lipohypertrophy (excessive growth of fat cells beneath the skin, an insulin injection complication)