I used to get a 600k out of my 1030. I'd bring a lipstick battery for a longer one. I had never updated the firmware until buying a Garmin Radar taillight and it now seems my battery does not last nearly as long.
There are some riders who still navigate by cuesheet. I saw a couple on a 200k recently but they are in a minority.
I bring the cuesheet always as a backup and always use it at some point on a brevet.