One of the Early signs I know of is to step on the clutch and listen for a slight ticking by the crank pulley. Now depending on the engine as far as noises go this may not work for all. Some of the Chicago guys have notices the crank sensor making noise just as the crank begins to move. If the engien has lifter tick you are screwwed and probably not going to hear a thing. You can have someone step on the clutch as you watch the crank but if you can see it then its not early..lol

I would say do an oil change and cut open the oil filter.....look for metal.

I agree with above this is probably the hardest topic to search for a needle in a haystack. Honestly its been argued here and i have discussed it with many other people.....Crankwalk is not as common as many believe, it does happen way to much but its not going to happen to every car.

Some people believe that if you dont have it by 90,xxx then you are safe...i dont know?

Terry