Great questions.
For the first two:
Yes. Some.On the last question, there is a magical ethic I ascribe to (and which is traditional in the initiated mysteries) to give healing freely and never unbidden. At the very least, one should know that the person is open to it, would not resent or refuse it. One must tread lightly in taking people's problems away from them, since they work so hard for them in the first place.