door latch does not work on outside pull

Have been thru that many times over the years.. Go out side and push (not pull) on the door with one hand while you open the latch. If it works what you will find is the movement going down the road has worn a grove in the latch bolt from the striker plate. So if you pull the bolt is set in the grove from the striker plate and you can not move it. You can file it smooth again. Also best way to keep the door shut when moving is a dead bolt. And they will come up with the same problem over the years..