I was going on holiday with some very experienced ...
I was going on holiday with some very experienced skiers in a few weeks and needed to get the basics learned before I headed out and made a fool of myself. I decided to try the "ski in a day" lessons. The lessons went at a really good pace, and the instructor ensured that everyone was continualy progressing. As members of the group started to get better she spent more time working with the people who were struggling while allowing others to practice freely. As we got better, she'd ensure she came up and gave us something else to work on. The final hour and a half was down to us what we worked on. Some members of the group continued at the bottom of the slope improving their technique wiht the instructor while others attempted some parallel ski work, something I managed to start to get by the end of the day (albeit with inevitable bad form.)
All in all I was incredibly impressed by the day. I had gone from struggling to slide 3m down a small slope to the early stages of parallel ski-ing (and I even went over the small ramp) in about 5 hours. Not everyone's progression will be the same, and I wouldn't recommend changing technique without instruction of course!