Lessons are how everyone gets better. Generally, the more lessons that a fencer takes the better he or she will be in a given time. Some fencers learn rather quickly with fewer lessons, while others need more to reach the same level. That does not make one fencer better than another; it just means that some work harder!
None of these formats is better than another. They are merely different tools that are used to help teach the student, and develop their individual skills.
Individual lessons are one on one with a coach. The lessons are relatively short but targeted to the individuals needs. It is the quickest way to learn a physical skill, but not necessarily how to use it at real speed in a given situation during a bout or competition.
Group work is where the students work at solving problems together, each taking the role of an opponent. The advantage with this format is that drills and instruction can be done at realistic speeds and distances, something not easily reproduced when working individually with a coach, while focusing on specific skills, techniques, and objectives.
Critical Evaluation is when the coaches talk with the individual as they are fencing, or just after they finish a bout. The discussion is not only about what the fencer did wrong, but also about actions that should have been taken and were not. So while there is less technical skill learning, there is emphasis upon using correct skills in a given situation, something the other formats do not provide.