After I bought my 1st unit I made a habit of recording for studying at home ...especially when fishing a different area from the previous trip ...
I would fish until 30 minutes before dark, put my poles up, and motor to a spot several hundred yards from the launch ramp ...
Start recording and record at a constant selected speed all the way to the launch ramp ...
This not only gave experience in recording (and a significant library of recordings) but also allowed marking waypoints on interesting stuff in the Recording playback that could be verified later as possible "fishy" Stuff ...
Rickie