A Jazz bass in for a fairly standard setup with low action.  One issue I discovered while changing strings was that the string ferrules in the back were super loose and fell out onto my bench.  Not a good thing as they can be easy to loose if you are not paying attention.  Similar to refitting peghead tuner bushings, I used some superglue snug them up.  Note that I do NOT glue the ferrules in.  The cured glue is used to add back material to the holes and give the ferrules something to bite into.  I often opt to add glue to the tuner bushings but on these ferrules I opted to add glue to the holes in the body.