Bad Distributor

I have a 99 Nissan Pathfinder. In the past 5 months I have put a new distributor in it twice. The first time the car was bucking and jerking and we thought it was a miss. Changed all the spark plugs and the wires and it still did it. Took it to a mechanic and he put the distributor on it. About two months later it just died. All the dash lights came on and it wouldn't turn over. It would crank but not turn. Had it towed to the mechanic and he put a new distributor on. Today the same thing happened. I had the last distributor replaced March 30. Had it towed to the mechanic and he put another distributor on.
What is causing these to go bad?