When should I use dispel magic?

[johnec]

It is a spell that is not in my current casting order. Should it be? When should I use it? Also, I saw in the AA guide sticky that they put 3 points into it. Is it worth it? What does 3 points do to dispel magic? Thanks.

[Sab]

I mainly use dispel magic as a trigger for tainted heals.However if you add the AAs to it it can dispel more types of effects.Other than tainted heals I use it for stripping some damage shields etc from mobs.