Final answer:
To ensure safety, changing router bits should only be done when the router is unplugged and power is disconnected. Confirming that the power is off prevents accidental startup and potential injuries during bit replacement.
Step-by-step explanation:
Changing router bits must only take place when the router is unplugged and power is disconnected. This is an important safety measure to prevent accidental startup while changing the bits, which could lead to serious injury. Before attempting to change the bit, make sure the router is completely powered off and the cord is removed from the outlet. After confirming that the power is off, you can then proceed to loosen the collet with the appropriate wrenches to remove the existing bit and replace it with the new one. Always follow the manufacturer's instructions for changing bits and use the router in accordance with its safety guidelines.