Stuff happens. Compasses break and vanish mysteriously. GPSs get sent down mountainsides (don't ask). Maps get ripped out of hands by the wind, or escape from pockets, or turn into pulp.

Redundancy is the best rule, provided one's not super-familiar with the area they're hiking.

As to having a feel for maps--I've learned in training that one needs to consider the visual, the auditory and the kinesthetic learners when preparing a training plan. Your auditories, for example, might have a hard time translating that two-dimensional paper to the three-dimensional world.

Cheers,