How often should we receive Holy Communion?
In general, we could say that we should try to receive Communion as often as we can, provided that we have kept the appropriate fasts, have been to Confession, and have no impediment to receiving Holy Communion. Although we are brothers and sisters within the Church, the partaking of the mysteries of the Church is a personal decision which is why they are always given to us personally by name. In addition, some Orthodox Churches have different customs and practices concerning the frequency of reception of Holy Communion. Often, people do not receive Holy Communion because they feel unworthy to do so, but as St. John Cassian teaches, we are all unworthy of such a great mystery:
We should not keep away from the Lord’s communion because we know that we are sinners, but we should hasten to it all the more avidly for the sake of our soul’s healing and our spirit’s purification, yet with that humility of mind and faith that will cause us, while judging ourselves unworthy to receive such a grace, to seek it instead as medicine for our wounds. Otherwise communion may not be worthily received even once a year, as is the case with some who live in monasteries and who are so in awe of the dignity and holiness and worth of the heavenly sacraments that they think that no one should receive them but the holy and stainless, rather than that it is they that make us holy and pure by receiving them. 
Saint John Cassian criticizes those who only receive Holy Communion when they consider themselves ‘worthy’ as guilty of an ‘arrogant presumption’. However, there are other reasons why Orthodox Christians do not partake regularly of the Holy Mysteries, and many of these stem from long-held customs rather than individual conceit. Most importantly, we should not judge either those who do not receive Communion regularly or those who do.
 St. John Cassian, The Conferences (trans. B. Ramsey) (Mahwah: Newman Press, 1997) p. 812.