Haven't hit tris exclusively in 3+ months. Between chest every 6 days and shoulders every 6 days, they have gotten plenty of work. I've added 3/4 of an inch to my arms in 3 months (on cycle) with absolutely no isolation work for them.
Day 1 : Vertical back Day 2 : Chest Day 3 : off Day 4 : Horizontal back Day 5 : Shoulders Day 6 : Off Day 7 : Repeat
I've tried the bi's and tri's together routine and hate it. After working one, I can't get a full contraction out of the other. For a juicy cycle I upped my training frequency so I can hit every group in 3 days, so chest, anterior delt, and tri's have been together; but soon I'll switch it back to where I was with tri's and shoulders together. I like legs and tri's together...if the gym isn't overcrowded with nut sucking fags trying to get a baby pump consuming the squat rack to knock out some bicep curls which inhibits supersets.
i like to hit mine with biceps. that leaves me with a 5 day split. if i need a break ill do mine after back. i get the best growth thraining them with biceps on there own day getting as much blood to the arm as possible.