When I started caching, There was only a little over 100 caches in Maine, so that left several hundered free to put landmarks in my 'Ol Yeller - mountians, lakes, intersevtions, etc., so that if I was at a vantage point and saw a landmark I wanted to verify, I could load that waypoint and make sure where I was.
Now there's so many caches I can't load everything anyway, but I do have a legend now as well, so I can make any landmark a waypoint using the map on the GPS. I just have to load the caches based on what section of the state I will be caching in.