LHC ultimate party setup.

Not saying you should refuse to join a party that has no SI or CO, but totally discounting them and not bothering to get the buff when you do have a Bucc or Pally in your party, is unwise.

Of course its good to take SI if its around then again, if your party consists of mostly BM/DB/Shad/NL/Mech/BaM(with elemental staves) then SI would be useless. Still, several other jobs would benefit from it, so it has its perks. Its just that some people would think that buccaneers are too weak to stick into a party and would rather bring someone else more efficient in killing. Same for CO really, not to say I'd refuse them, but they don't go where I go so we're in a disagreement.

Once we move on to the overkill point, more people in the party won't really help the xp gain much since they all die too fast for the spawns to keep up. Some of my own guildmates tend to do 2-3 attackers at castle golems with the rest being afkers (besides hs mule of course) because they're doing their huge 600k-800k+ damage per hit, primarily a few of the BaMs in my guild. At that point, buffs is nice but then they don't want you because they don't need a attacker.