This one held back my growth as an artist, possibly more than anything else. I worried that working from photos would harm my skills in some way. I avoided it so much that I ended up only working from a live model 3 hours a week and I barely improved during this period. The honest truth is that most artists that subscribe to this belief, end up being still life or landscape painters, because hiring live models is prohibitively expensive these days. I've found that the combination of working from photos, along with doing master copies, is enough to overcome the urge to "copy" the photo and that working from photos even encourages out faculty to interpret nature in a more interesting way.

This is a purely modern approach to academic training. The European ateliers and academies of the past rarely worked on studies for more than 15 hours. The learning benefit we derive from a study diminishes greatly after about 15 hours, especially when dozens of those hours are spent filling  in the grain of the paper with a super sharp 4h pencil. One exception to this I have is that if a student WANTS to work in this way, that's a different story. 

This is a tricky one, since drawing skill is so vital to the success of the student. The problem with this myth, is that it implies that drawing with dry media (ie graphite or charcoal) is somehow better at training the student than learning to draw with oil paint. I know of many artists that can draw very well with dry media but can't paint very well. I also know of artist that are terrible at "drawing" but can drawing with paint better than most people alive. The point I'm making is that if the student desires painting over drawing (dry media) there are valid ways to learn drawing with oil paint. As home taught artists, we need to harness our focus with projects we're interested in, more so than if we were in an atelier and had the same social and financial pressure.

This is another tricky one, since I often recommend certain students do cast drawings/paintings or Bargue copies. But they can be tedious, and like I've said before, the home learning student must work on projects they can muster the mental energy to perform and if a student is too bored with a project, they will be easily distracted, won't finish the project and will in the worst cases, reinforce the idea that this art training thing "isn't for them".