This is probably a simple question for this group. A co-worker recently had a residence rewired and has experienced the light bulbs in one hallway burning out every couple of weeks. Any thoughts on what is causing this?

Loose neutral (in home run, splice, etc.) poorly made edison base sockets for the bulbs, poorly made, maybe imported light bulbs.

Bulbs could be loose or subject to vibration somehow from the floor above, slamming doors, etc. Try a rough service bulb in the fixture.

Bill

As the others said. Most likely a loose neutral somewhere, obviously try looking at the fixture first. Last resort, try a 130v incandescent lamp. Covers many a problem.
Cheers
NS4M

NS4M has the right idea. There is a formula for incandescent bulbs in our apprenticeship books that says:
(Actual Life/Rated Life) = (Rated Volts/Actual Volts)^13.

Take a 130 volt, 1000hr rated bulb and feed it 123 volts and you get:
AL/1000=(130/123)^13 or 2053 hours actual life.

In contrast, take a 120 volt 1000hr bulb and feed it 123 volts and you get:
AL/1000=(120/123)^13 or 725 hours actual life.

Those 130v bulbs are life savers in hard to reach fixtures.