Originally Posted by
Selesnya
7k spirit has nothing to do with epeen. There's some really simple math behind running with low spirit, that's because spirit is a wasted stat if you have mana left at the end of an encounter. 10k spirit are ~70k mana/minute, which means with the numbers I outlined in the post above only accounts for ~30% of disc's mana regeneration. Half of the passive mana regeneration comes from the naked character, that's why spirit is a bad stat, not only for discs.
Theoretically you could drop the whole 10k spirit for 15% crit. Or some crit and a ton of mastery, which probably makes more sense since the lack of HP healing is quite apparent to disc already at this point. You trade 30% regen for 15% to 25% or so throughput. But that's quite unrealistic since a great portion of non-spirit cloth gear haste haste as a stat, which would completely dry you out of mana.
But dropping to 7k from the typical 9k is a mere 7% drop in regen, in favor of 2000 secondaries worth of throughput. If you see yourself sitting at more than 10% mana at the end of most encounters, it's time to drop spirit in favor of throughput.
Fake edit: I actually forgot mana trinkets in all of this, which now account for ~45k mana/minute. Those devalue spirit even further, and that's a lot actually.