|You won't need to reset anything unless you change which router you have connected or one of them malfunctions and needs to be replaced.|
"I was wondering if There is a way to back up my present router settings to a disk and later import them into the router"
I have never seen such a feature as being able to import or export settings in the D-link or Siemens router configurations.
You should know by now how to access the configurations of the routers (e.g. 192.168.x.x) - just copy everything down that you see in those configurations!