There are 2 main types of retainers: Fixed and Removable
Fixed retainers are strands of woven wire that are glued to the back of your teeth to hold the teeth in place. As its not removable, you don’t have to worry about losing them. There is always a chance that the glue used to hold it in place may fall off, in which case you would want to get that fixed immediately.
They other form of retainer which we generally recommend, is a removable retainer. An Essix style retainer is a clear plastic tray that sits around your teeth to hold them in place. While some offices request full time wear, we only ask that you wear your retainer 8-10 hours a night to hold your teeth in place.