I'd add: review and familiarise yourself with the planned route; keep track of progress; ensure you have the appropriate cables etc. to keep batteries charged / unit powered.
I'll confess on two occasions to have got into situations where the SatNav has either just plain lost the signal and wouldn't re-establish, and another where the the batteries ran out and the charging cable had 'malfunctioned'
On both occasions I had a backup paper map; but in both instances I had NO/LITTLE IDEA of
where I was, other than county / town, and no real idea of my destination address -- post-codes don't work well on paper maps
Took a lot of map fiddling, head scratching and a bit of driving, looking at signs to work out where I was, plan a route, and navigate there. D'oh!
Hence, I now take a good look at the planned route and ensure I keep attention on actual progress, and remember to keep a note of the final destination too.
Actually, thinking about it, I also 'distrust' the spoken directions, and have a tendency to really only use the satnav as a visual cue / moving map, and glance at it as part of my ongoing observations. e.g. on a local pair of Mini R/As TomTom tells me to 'Turn Left, then Right'. If follows those spoken directions, one ends up 'straight ahead'. It actually means "Turn Right" at the first -- but because of the road layout / name changes reckons the entry onto the Mini is a Left turn. D'oh.
One has to get used to these foibles (which differ between manufacturers), and double-check the visual layout (without becoming fixated on the unit).
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