The installation time for a shower door can vary depending on the type of door, the complexity of the installation, and the condition of the existing shower space. On average, a standard shower door installation can take between 2 to 4 hours. However, if you are installing a custom or frameless glass door, it may take longer, usually around 4 to 6 hours or more. This duration includes time for accurate measurements, drilling, securing the door, and ensuring a watertight seal. It is always best to consult with your installer for a more precise time estimate based on your project.