“You1 are no doubt aware of our custom to affix the mezuzos immediately upon moving into the house, needless to say without a blessing. Thirty days later, however, one of them is removed for examination, and this of course may be replaced by a better one. One now recites the blessing as one affixes the new mezuzah, having in mind those already in position on the other doorways.[...]

“A mezuzah should be fixed on the right, as one faces2 the room into which the door swings.3 This rule does not apply to the front door; [i.e., irrespective of the above, the mezuzah is always on one’s right as one enters the house].”