The Gemara comments in Masechet Berachot (6) that a person who designates a particular place for his prayer not only has a better chance of his prayers being answered, but also receives special assistance from God ("the God of Abraham is at his aid"). Accordingly, the Shulhan Aruch rules (Orah Haim 90:19; listen to audio recording for precise citation) that one should set aside a specific place for his prayer, and should not pray in a different place unless this is necessary. The Shulhan Aruch emphasizes that this means not only designating a particular synagogue as the place where one prays, but also setting aside a specific place in the synagogue where he prays.
It should be noted that this Halacha refers specifically to the Amida prayer. One should designate a particular location for the recitation of the Amida, but this is not required for other prayers a person recites.
The Kaf Ha’haim (Rav Yaakob Haim Sofer, Baghdad-Israel, 1870-1939) writes that this requirement stems from the status of prayer as a kind of sacrifice. Prayer is considered an "Aboda" ("service") just like sacrifices. Therefore, just as each sacrifice was offered at a particular location in the Temple courtyard, similarly, one’s prayer should be recited at a specially designated location.
The Kaf Ha’haim cites from the work Ru’ah Haim (listen to audio recording for precise citation) that praying at a specifically designated location helps ensure that one will not be exiled from his place of residence, and will enjoy the stability of living in one place permanently.
Furthermore, the Kaf Ha’haim comments that this Halacha applies even to a person who, for whatever reason, prays at home. If one is unable to attend services in the synagogue, and must pray at home, he should have a designated place at home for his prayers, where he prays each time he must pray at home. The Kaf Ha’haim adds that this location should be somewhere where the person will not be disturbed by his family members.
Designating a place for one’s prayers is crucial for enabling one’s prayer to achieve the desired result. The Kaf Ha’haim writes that if one does not pray at a designated location, then the Mash’hitim (destructive spiritual forces) that had been created through his sins grab his prayers as their sustenance, to feed off of them.
The Magen Abraham (Rav Avraham Gombiner, Poland, 1637-1683), as the Kaf Ha’haim cites, noted that this Halacha does not require one to always ensure to pray the Amida in the precise same spot. Rather, it means that one should pray the Amida each time within the same four Amot (approximately six feet).
The Kaf Ha’haim adds in this context that the seats in the front of the synagogue, within four Amot of the Hechal, should be reserved for righteous Torah scholars; ignoramuses should not sit in those seats.
Summary: One should make a point of designating a particular place in a particular synagogue for his Amida prayer, as this helps ensure the efficacy of his prayers. One should also have a designated place at home where he prays when he cannot attend the service in the synagogue. This does not mean that one must pray in the precisely same spot each time he prays the Amida, but rather that he always prays within the same four-Amot range (which is equivalent to approximately six feet).
