Installing a door viewer is one of the simplest, yet most effective, security upgrades you can make to your home. It allows you to see who is knocking before you unlock your door, providing an essential layer of safety and peace of mind. However, the effectiveness of this device depends entirely on one crucial factor: its placement. If the viewer is too high, children or shorter adults can’t use it. If it’s too low, taller individuals have to stoop uncomfortably.