What does “One Year and a Day” represent?
An excerpt from another article I had written on this subject:
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Traditionally giving the initiate /dedicant a time interval of one year and a day or 13 lunar months and 28 days. This is used in many different places and generally used as a symbol for representing the time that is constitutes the preparation period.  
At present some Wiccan traditions take this period of time as a basis for providing the initiate intense preparatory education and at the end of the period realise the initiation ceremony.

However, perhaps the term “one year and a day” should be qualified with “at least”; because the necessary preparation period varies according to the individual and it might take years as well as a much shorter period of time. I need to stress it again that this expression is symbolic rather than descriptive. 
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Finally it should be said that making research, gthering information and learning is a process, it takes time and this time period is not limited or rule-bound. Those who have experienced the Initiation process will have a deeper understanding of what I intend to mean. When the subject is “paganism” there is no period of waiting unless it is due to personal choice but there is such a period when the subject is a tradition or an order. There is a beatiful saying about this by the Hpss of the eclectic establishment:  “…The Lord and Lady make you Priest or Priestess, but I make you an Initiated One”