You must remember the network name when using this method.
I just bought a laptop and I upgraded the firmware of my 655 router to 1.04 straight out of the box.
By default, all routers come with a certain set of credentials, including D-Link routers.
Because it only takes a few seconds to change the password, one could argue that there is no downside to doing it.
However, it's rare to actually need access to the router settings, especially if you're not one to make network-wide changes, which only makes it easier to forget (unless you could keep it in a free password manager).
To reset a router is to erase any custom settings and replace them with defaults.
It can usually be done through a small physical button that has to be pressed for several seconds.