If you have a fixed retainer (wire behind the teeth) then you will need to take extra care to keep it clean. You will need to remove your retainers when eating or drinking anything other than water.
It is important you brush well twice per day and use a fluoride toothpaste. You should also gently brush the retainer, taking care not to snap the plastic. A daily fluoride mouthwash should be used last thing at night, after toothbrushing.
If the retainer is removable but you have been asked to wear it full-time, it should only be removed for cleaning. When the retainer is not in your mouth it should be in its protective box. Dogs love retainers, so make sure you keep the retainer box up high and out of reach. Do not click the brace in and out with your tongue as this can cause the brace to break.
You should always bring your retainers to your follow-up visits.