Mark the size of one inch directly on your finger
This simple trick is not a new one; grandmothers and mothers worldwide are familiar with it. When they need to sew a new hem, using the ruler to mark their fingers with the lines can be really helpful. This hack is quick, simple, and effective.
Those sewing will not have to waste time with a ruler because their thumb will undoubtedly be enough. This saves time and eliminates the risk of making a mistake with the measurements. If the lines start to fade, simply go over them again to make sure they are visible.