Retention period is the most important phase of orthodontic treatment. The problem of "retention and relapse" is likely to continue to tense the Orthodontist because of the complexities of the etiological factors and one has to be thorough with all the implicating concepts. The choice of the type of retention, duration of retention, has a great bearing on successful post retention cases. Any violation of the biologic limit, which trespasses the low of optimality, will end in miserable failure.