I’ve upgraded my router several times since getting my Tablo. When I go through setting the routers up, I specifically keep the same SSID and password, such that everything reconnects and works when I bring the router online.
Unless there’s a reason to change your SSID and/or password, that’s the easiest way to go, which saves you a lot of work, especially if you have 30+ devices on your network like I do. I’ve got numerous smart bulbs and switches, ring video doorbell, smart phones, tablets, computers, Rokus, etc., and it would be a HUGE job serring all those devices up again if I were to change the SSID and password.