Innervate
is nearly 100% used on our Shaman. Purging+Totems ontop of healing eats up tons of mana.
Staff of Natural Fury helps me out a lot. I think I used innervate on myself once in 5on5 and once on the hunter.
But Innervate is pretty lackluster for a 6 minute cooldown. No one uses spirit for pvp healing and therefore it only delivers about 2k mana. Much better than nothing tough
My mana problems heavily depend on 2 factors
a) how often am i forced to bear
b) how often am i forced to break snares/roots (prevent hunter fear)
usualy I am low at the end but rarely do I need to actively wait for my spirit to regenerate me enough mana to operate.