There exists no level of knowledge that's useless because of relativity. For example, someone that is learning a skill, even after day one of their lesson, would have something to share with a person that did not spend that day studying. However, the person sharing the information has to keep in mind that they are not an expert on the topic so it would be wise to spend more time understanding the lesson first. Sharing the general concept of the lesson is still a great way to share interest in a particular skill or trade that the other person might've not had previously.
Since the person that is just starting to learn can relate to the person that hasn't started or is considering starting to learn the topic, they might make a good gateway for learning. The expert may know a lot of information about the topic/skill but the new student will have a different perspective and may be able to offer a bridge for the prospective student to meet with an expert and learn more. This is why education is best as a collective effort between groups that work well together. The group dynamic is usually powered by common interests and goals that seem to align at some plane. This can be a great way to reach new solutions to problems and even challenge the expert when the knowledge and wisdom of the other parties reaches peak levels. At that point knowledge is being shared equally among everyone.