I get asked all the time why should I take classes when I have a video? I normally ask how much motivation and accountability do you have to the video? Do you feel you are doing it right? Can you understand and follow the instructor? I normally here the following back:

I do them every now and then that is good enough right?

I am not sure if am doing it right but I am doing it.

I can never figure out what the instructor is doing.

Take some lessons from a trained instructor and sprinkle in videos as needed. Do it when traveling and when you can not get to the studio!