I like my way of doing it because I find I'm using triceps in a bench press anyway, might as well just make it close grip and really hit them on the same day. Then with pull ups it's the same, already using biceps, so I might as well hit them afterwards on the same day.
But I'm trying to build up the rest of my body, my arms are okay, but my lats, back, legs, chest and core all need to step up a bit. So I just throw the arm exercises in their along the way.
If you're the opposite to me then yeah I would spend a bit more time on arms. Still I'd only do them twice a week.