the lightbulbs blowout (literally-explode into bits) every two weeks or so
...
The lady has been in the home 12 years and this has consistently occured
That would be 26 weeks x 12 years = 312 x 2 bulbs = 624 bulbs (so far). Can you pinpoint when this annoying exploding lightbulb problem first popped up?
Some other questions that might help find some answers:
Can you post a photo of the offending fixtures and the surrounding area?
How do the fixtures receive their wiring (e. g. conduit, etc.)
Are these the same fixtures over the past 12 years?
How does the person remove what is left of the bulbs once they explode?
Does this fixture sit anywhere near grass?
Do they ever use water sprinklers?
Is there any plumbing in the garage?
Where do they purchase their bulbs? Are they using the same brand each replacement? Did they buy them in bulk somewhere?