Just to add to Backpacker's post, you can put in your own permanent waypoints with SD which I'm sure many of us do, mine has about a hundred and counting. As he says the 'natural' waypoints IE good visual references aren't always nav beacons etc.
I would also go along with the general consensus that you need to learn to navigate first; not as a 'I have to do this to pass my skills test then I can use my GPS' but to be able navigate with a map, stopwatch and compass confidently and correctly. Every month or so I do a longish flight somewhere I haven't been before using just the basics to stay on top of my nav skills. Apart from anything else I enjoy it.
Going on from what Pitt's said, eventually and fairly quickly you will get to know all of the local and extended nav features. I reckon you could blindfold me and put me anywhere within a 50 mile radius of my airfield and I could happily navigate back purely on memory. That's not because I'm some kind of super pilot; it's just that you get to know what all of the landmarks look like from the air, the further afield you fly, the more gets filed in your memory. It's surprising what does get filed away without you being conscious of it.
You wouldn't bother with a Tom Tom to drive to the local town, eventually your flying will get like that.
Last edited by thing; 17th Aug 2013 at 23:21.