Trouble starting my XJ

[Parrothead]

Sometimes my Cherokee will start and sometimes it won't. I can turn the key and nothing happens. I can lightly tap the side of the starter and she will start right up. Can someone tell me what the probable cause might be? Thanks in advance.

 

[4xBob]

That's classic worn out starter- don't mess around, replace it with a quality unit. 4xBob