Avoid single point of failure to multiple systems;
Single item,i.e. cell phone fails,now commo fails,compass fails gps fails etc.
A simple button compass was used as a escape compass by the army in WWII can be concealed anywhere. You just can't improve on it.
The dry type NATO from PSI are great.
Electronics fail from time to time.
Remember that old adage that a tool that does many things does none of them well.
Blue Skys