I personally think that it is not important to have age limits for training courses because the young can learn from the old and the old can learn from the young. I personally think that it is not important to have age limits for training courses because everyone can learn from one another.
Perhaps the most important age limit for courses is gun safety. Though the appropriate age differs from country to country, age limits are present in this situation. Some kids as young as 16 can learn proper gun safety skills. While this may seem young, it also has benefits because it helps.
There are training courses for just about anything you can think of, but they aren't all suited to people of all ages. Every training course needs to have established age limits to avoid confusion. Training courses for Police officers would require different age limits than training courses for computer programmers. The group responsible for conducting the training needs to make sure applicants are within the required age limits.
No, age limits on training courses prevent smart people from reaching their full potential. Universities have long been accepting students as young as 13 or 14 because the students proved they were capable of doing the work necessary to succeed. If Harvard admissions representatives believe that a 13-year-old is capable of completing their rigorous coursework, instructors for training classes should also be permitted to allow exceptionally bright youngsters to participate.
I do not believe it is important to have age limits for training courses. I believe people should be allowed into training courses when they show a level of maturity and knowledge necessary to start the training program. Of course it's hard to generalize given that there is a wide variety of training courses available and the question does not indicate what kind of training courses we are referring to.