Only time I can remember not being careful was a long time ago. Back in Lothering, actually, so there's nothing for you to worry about... and if I ever do make you worry? Tell Merrill. She'll pout at me and make me feel bad until I apologise.
Elemental magic's a bit overrated, to be honest. I preferred force magic, mostly - you know, the kind where you can pick up your target and introduce him to the floor at a suitably high speed.