If i were to work for the Post Office would i have to join the union?

I worked for the Post Office and did not join the Union. It is not required.

And what promotion do you have in mind? If it's to management, then you wouldn't be allowed in the Union any more.

No, you wouldn't be required to join the union. But why wouldn't you want to join the union? It costs about $ 400.00 per year. Go to the appropriate union craft site of the work you hope to obtain.

NRLCA.org

APWU.org

NALC.org

Most new hires, who get fired, do so in the first 90 days. It would be in your best interest to join so that someone could help walk you through that probationary period. It's a tough job and you might need a friend.

No, it is not required and not a good idea, unions are destructive and should be banned.

No you don't have too, but during breaks or in the break room pressure is on.