Sorry to say, headgaskets will last 200,000 miles if they're installed with the proper preparations. I recently bought an '87 4Runner from a guy who did his own headgasket change, and it lasted him a week before it blew again. He got disgusted and bought another truck. He hadn't cleaned out the head bolt holes in the block, and the head bolts were bottoming on oil/antifreeze in the holes. Even though his torque wrench had indicated the correct spec, the bolts weren't exerting proper clamping force on the head gasket. When I took it apart, some of the head bolts were barely more than finger tight.