Example 1: pilot may not be thoroughly familiar with the navigation
equipment

Example 2: pilot may be an old timer and may not like 'modern'
technology like GPS

Example 3: pilot may have found the equipment to be flaky in the past,
and is not comfortably using it

Example 4: Just because he doesn't feel like it.

Why does it matter what the reason is? My point was, if he chooses not
to use an equipment, he should not file it. Is there a rule that says
otherwise?