When I first heard people say this, with the idea that since XP is worth more at high levels, not completing your Class quests for the Enlightenment buff until you were high level seemed like a very logical plan. That somehow it would make you level proportionally faster at higher levels than it would low levels.
Now stay with me here, but I'm not sure this is true any more after pondering over it. It's a 50% bonus. No matter what level you are. No matter how much XP you're getting, you're getting 50% more, and thus, leveling approximately 50% faster through whatever content you're in.
So does it matter at all whether we "save" this buff for higher levels? I'd think the only concern would be to make sure when you get the buff, you're constantly leveling every second that you have the buff.
Thoughts?