I ended up referring them to the nearest electrical supply w/ showroom.

Use rough service bulbs.

Wind vibration is a real killer of post mounted bulbs.

Good point on the lamps (bulbs). I had used the wrong terminology and was actually referring to the quality of the fixture.

On a separate note, another client had a faulty post-mounted fixture and also a matching exterior house light, both with copper housings and beveled glass, etc. We took them to get rewired (new wire and sockets) at a local lamp shop (Lamplighter in Old Town, Alex) and they're back in working order. Repairs are a inexpensive alternative that seem to be forgotten all too often.