In one street, two houses can not have the same address. The IP address too, in a network can not have two computers with IP addresses. If two devices have the same IP address is plugged into the network, it will lead to conflict IP address (IP Conflict). Meanwhile, both devices will not work.
Currently, families often use Wifi emitters 2-3 to get the Wifi waves cover the entire space. Therefore, in the family can have up to 2-3 wifi network. That leads to the default address from the manufacturer can conflict with each other. However, you need not worry because now these devices are equipped with Wi-Fi feature that automatically reset the IP to a different address when conflicting.
Example: Tenda wifi device with an IP address default is 192.168.0.1. If you plug in the network address range 192.168.0.x/24, it will automatically detect the conflict and pushed to the IP range of 192.168.1.1. Similarly, if the network has 192.168.1.1 range, it will jump to up range 192.168.2.1.