I noticed that many spells can be charged, e.g. the Sparks spell I got in the beginning can be cast continuously until I’m either out of magicka or the target is dead.
As you level up your skills just by using them I wondered if it makes any difference whether you cast a spell without charging it repeatedly or if you just hold down the mouse button and lightning bolt the enemy until he’s really dead?
Which way do I level up the skill faster, or is there even any difference at all?
I could find no credible sources about this, so I performed a completely unscientific experiment to figure this out:
I loaded up a low-level saved game and used Flame continuously until my magicka was exhausted, then took a screenshot of the skill screen. I then reloaded the game and used Flame in ~1 second bursts until my magicka ran out, and took another screenshot. I then compared the pixels in the screenshots using Paint, and determined that they had both advanced an equal number of pixels. This suggests that it’s extremely likely that it doesn’t matter if you cast with duration or frequency – you’ll gain at the same rate.
In summary, there is most likely no difference.