Yes, I think it is a good idea for teenagers to have jobs while they are still students. However, my choice is subject to two limitations.First, I am not considering teenagers here who need to work because they have to support themselves and have no other choice.Second, I am only taking into account the option of working part time.
First , teenagers learn the value of both time management and money , if they start working from an early age. For eg, students who take up part time work while continuing with their studies, for say pocket money, realize the importance of money. Therefore, they will, most likely, strive to do better in their studies for increasing their earning prospects for the future. At the same time, in order to continue their present inflow of money while balancing it against the need to continue education, they will also strive for better time management skills, which is an excellent trait to inculcate.
Second, in today's day and time, when both parents work, teenagers are most often left alone to tend to themselves during their free time. While, pursuing hobbies such as painting, reading, singing , etc are also options for teenagers during their free time,in my opinion, doing part time work is also a very good option. Having regular part time job, inculcates in them, early on, a sense of responsibility and discipline and ability to manage expectations. Also, they most definitely will start respecting their parents' efforts to earn and give better life to the children, if they do not already do so.
Ofcourse, while I am strongly in favour of teenagers taking up part time work, I also believe that what teenagers do with the money earned still needs to be monitored by parents.
Although, those who are in favor of the argument that teenagers should not work, may come up with a lot of arguments against teenagers working, I am of the opinion that teenagers who start working part time grow up into adults who are much better equipped to handle stress and expectations of today's world.