I've been encouraged to jump in and comment on my Flea signature Jazz bass.
As folks will know, they all look the same, being copies of the same bass... but they are a great way to get a 'played in' replica of an early sixties ('63) Jazz.
I felt it was bit 'slick' looking and the dings and scratches were a bit predictable and repetitive. The chips, especially, all seemed to be in groups of three, the same shape.
I couldn't do much about the dents, but I used a kitchen knife to chip off a bit more paint and make the wear look more random and natural. A grubby rag (used for cleaning up my lathe) dulled down the bright patches of wood that appeared.
I also used a hot air gun (set fairly low) alternating with pipe freezing spray to check the nitrocellulose, front and back. This is a bit scary, but actually turns out to be fairly easy to do and controllable. The hot air makes the new cracks disappear, and at normal temperatures they are faint and less noticeable than when freshly done. I didn't get any flaking off.
To subtly accentuate the checking I used the same grubby rag to apply dark oak woodstain and immediately wipe it off again. This also aged the paint a bit more as well.
I like the result.