Some hard parts need to be redrawn every one to two weeks while others can last for up to four weeks without a follow-up visit to the barber. Upkeep will depend on a few factors: the width of your hard part (thicker parts will be more noticeable growing in than finer ones), the accompanying hairstyle (some parts organically blend into certain hairstyles when growing out), and your personal preference on how clean and crisp you want your hard part to appear.