Car will not start every two weeks

My 1995 Toyota Camry will not start, the engine turns but does not engage. I have had the fuel pump, fuel filter, and a relay switch replaced. After each repair the car runs for twp weeks and then will not start. I have had it towed and the mechanics start the car with no problem and they are unable to diagnose the problem. In a month and a half, I have had the car towed 3 times.

I do not have any idea what the problem is. If someone has had a similar problem, I would love to know how it was resolved.

This can happen when the center shaft bearing inside the distributor wears out. This can be checked.

Is it weather related, such as after a rain?

It could be a bunch of different things so you’ll need to diagnose as to where a mechanic should look.
The simplest thing to check for is spark so get a spark tester* at HarborFreight or any parts store. Plug it in series with any spark plug and see what happens when you start the car. You should see it flash. If you don’t, your problem is likely with whatever creates the spark.
If you do see it flash, I’d look in the direction of the fuel delivery, etc.

*http://www.harborfreight.com/inline-ignition-spark-checker-69014.html

V6 or 4 cylinder?