Dear Healers who don't DPS

[Taika]

If a healer stands there for some gcd's doing nothing. That's not necessarily them being lazy:

DPSing in this game as a healer, differently from titles like WoW, really can cost you a LOT of MP (esp. on aoes). I often ran into the situation that the tank showed himself durable for some moments, then he went really squishy (together with dps taking avoidable dmg) and I simply did not have enough mp to recover the party because I spent most of it on dpsing! (inb4 lucid dream: that's a 2min cooldown)

All healers have MP-free heals, WHM has Lucid, Assize and Thin Air, SCH has Lucid, Aetherflow and Energy Drain, AST has Lucid and Ewer (yeah not as good as it relies on RNG but anyways). In great majority of content, you should not be running out of MP on any healer. Exception may be learning new Savage (or even Extreme primal) fights, but in those situations no one should expect you to put that much thought into DPS anyway.

I'll add that if in leveling dungeons you need to focus on only healing, to the point that you're running out of MP, there's something seriously wrong in either your tank, your party DPS, your healing tactics, or several of those.