I typically leave my resto shaman to have all DPS buttons (rank 1 earth shock, full rank chain lightning, rank 1 Frost shock, max rank flame shock, etc) to DPS with and replace my "spam button" (i.e. lightning bolt, holy shield) with a healing button.

Currently resto shaman (at raid level) can spam chain heal rank 4 indefinitely with regular mana tides. However, it can also be useful to maintain a healing way stack on your tank. This is my spam button:
/castsequence [target=focus,help,nodead][target=party1,help,nodead] reset=15/combat Healing Wave(rank 1), Chain Heal(rank 4), Healing Wave(rank 1)

I also have individual buttons (i like to use SHIFT+1, SHIFT+2, SHIFT+3, etc) for max rank Healing Wave, max rank Chain Heal, max rank LHW, Earth Shield. I can target anyone with these specific macros -- the "spam" button basically healbots through normal damage and keeps up my Healing Way buff.


In any case, I didn't put a dedicated healer into my group until 70, so take that as you will. Yes, I did do instances all the way up to 70, and no... for normal instances you do not need a specced healer. But it's good practice if you'd like to try it out. The thing I forget the most is to refresh ES.