Wear your retainer at all times, until the doctor instructs otherwise.
Take your retainer out when eating, and always put it back in its case! (Most appliances are lost in school lunchrooms or restaurants.)
Clean the retainer thoroughly once a day with a toothbrush and hand soap. Use warm but not hot water. Brushing retainers removes the plaque, and eliminates odors. Efferdent® or other orthodontic appliance cleaners can be used but do not take the place of brushing.