I would highly recommend you wear your retainers after your braces are removed. If you choose not to wear retainers there's about a 75% your teeth shift. The shifting may be gradual over months or years depending on where they started before you had braces, or it may even be as quickly as a few days to weeks. Considering the time commitment and cost you invested in straightening your teeth, it would be a shame to have all that hard work undone. Typically after about 6 months you would only have to wear your retainers while you sleep. If you decide you aren't going to wear retainers at all, then at the very least, ask your orthodontist if you would be a candidate for permanent retainers, which are wires glued to the back of your teeth. Hope that helps!