If you stop working by choice and leave your position or occupation, you retire. If you are lucky, you can retire early in order to sail around the world, but most people can't retire until they are old enough to collect retirement benefits.
If you go to bed in the evening, you retire. If your younger siblings are being loud and obnoxious, you can retire to the basement to get some privacy and quiet. If something is withdrawn from circulation, it can also be retired. When a beloved player leaves a sports team, often the number assigned to him or her is retired and no one else can use that number.