I trim the patch and the shaft. I've tried shaving my balls, but it gets too sticky and I have to use Johnson's baby powder for that nice, smooth feel. I'm not going to shave my balls anymore, but I do like a trim patch.
Its a matter of personal preference. I never have but have considered, some people really get turned on about this, certainly something I would try as it will always grow back.
Usually trim every 2 -3 weeks when I'm shaving my head with the electric. Head get's 1/8"... err, uh... hat-rack get's the 1/8" attachment, man-piece get's it's from the source.
Been lettin' the hat-rack grow though - at least for the winter. So have negleceted to cut the lawn down south for a bit. Finding it start to pull a bit at random. I should really go do that now...
I thin the brush a bit, but am frankly turned on by lots of hair, at least like mine -- abundant and soft and "fluffy." I shave my balls and cock; they look better, they feel better. Otherwise they get caught in the underbrush!
I usually shave my balls just bc it feels freakin sweet when they are all smooth and stuff, and then i shave my shaft bc rubbers work a whole hell of a lot better that way.
I do a little of both trimming and shaving, I'm not one for a thick bush so I trim it down to about a 1/4 inch and My balls I shave Smooth, My GF Loves the feel of them being smooth and she doesn't get as many Hairs either, If you know what i mean!!!