When people pick your job for the twelves, for the rest of your life, there are some good and bad things about that.
First of all, if someone picks out their job, well the twelves have a secure job for the rest of your life! Twelves won't have to worry about what they are going to be and what happens if they don't get a job because they already have a job. Not only that but now they have more time to study the job theywere assigned to. Twelves would only have to worry about what is ahead in their job and almost nothing else.
Then again, what if the twelves didn't get a job they enjoyed? What if they wanted a different job? That is a downside. Some of the twelves might not even want a job. What if the twelves want to live a simple life and their other partner is the only one who works? Sometimes one person always stays at home and cleans and takes care of the home while the other works. That isn't the case of the twelves are ASSIGNED their jobs. They have to work whether they like it or not. Sometimes people just want to do other things, instead they have to work with a job they possibly do not like. Twelves might love their job or hate it. It depends if the odds are in their favor. Other than that, this job picking idea might not be the best.