Unless you had so much fun the first round and want to repeat the whole orthodontic process all over again, the answer is, yes, retainers are necessary and a lifetime commitment. Teeth continue to move and shift over time as we age. Teeth are held in place by bone and ligaments. Ligaments have a memory and often want to return to their original position. Other forces that apply pressure to the teeth can cause shifting including: chewing, clenching, nail biting, outward pressure of the tongue and inward pressure of the lips. However long you want to keep your teeth aligned, that's the length of time you wear a retainer. In short, this means they should be going with you when you check into the nursing home.