After you get your braces off you will receive retainers to wear. There are different types of retainer options available. You will wear your retainer all the time for the first 3 months after your braces are off. Then you will just wear your retainers at bedtime. But you must wear your retainers at bedtime the rest of your life if you want to keep your teeth straight.
If you have retainers that do not fit because your teeth have moved, we can sometimes realign crooked teeth with your retainer, so do not throw it away if it does not fit!