User blog comment:Andrew.heo1/When to Get a 3rd GP10 Item on a Support?/@comment-81.200.170.248-20120815204440

Of course it's somewhat situational depending on what support you play, what your team is building and so on. But usally it's actually fairly simple. If you have tier 1 boots, philo, hog and another 840+ gold before the laning phase ends you get kages, otherwise you don't.