Why should bob of simple pendulum be kept near the floor?

Keeping the bob of a simple pendulum near the floor reduces the potential energy of the system, which in turn decreases the amplitude of the pendulum's swing. This can help prevent the pendulum from swinging too wildly and potentially causing damage or injury. Additionally, having the bob closer to the floor reduces the distance it needs to fall, which can minimize the impact force when the pendulum reaches its lowest point.