Never. My rule is no razor below the neck. I am a hairy guy and want to look like a man and not a prepubescent boy. Wife likes my hair too.
I shave at the base of my penis and sometimes my sack. I do trim the long hairs but not regularly. Someday I may remove it all down there, but only if I find a partner to do the work, since it's hard to see in some places. hahaha