Always wear both shoulder straps. While only wearing one may look better, it puts too much stress on that particular shoulder. Select the pack that is right for you. (See more in “Selecting the Right Backpack”) Your backpack shouldn’t hang more than 4 inches below the waistline. Putting it any lower or too much higher will strain the back. Use padded backpacks with individual compartments to distribute weight evenly. Use a waist belt for heavier weights.