If a person removed his Tefillin and put it on again later, does he repeat the Beracha?

The Shulchan Aruch rules that even if one's Tefillin simply moved out of place, to a location where one does not fulfill the Mitzva, he must repeat the Beracha before moving the Tefillin back into place. Halacha, however, does not follow his view on this matter. Rather, if one's Tefillin moved out of place, or even if one removed his Tefillin entirely and put them back on within a period of a half-hour, he does not recite a new Beracha, so long as he had intention when he took them off to put them back on. However, if he puts on his Tefillin later than a half-hour from when he removed them, he does, indeed, recite a new Beracha. Therefore, for example, on a fast day, when we have the custom to wear Tefillin both at Shacharit and at Mincha, we recite the Beracha when donning the Tefillin for Mincha.

There are two cases where one would recite a new Beracha even if he puts on Tefillin within a half-hour from when he removed them. First, if one removes his Tefillin to use the restroom, he must recite a new Beracha when he puts them back on afterwards. This applies even if he had in mind when removing his Tefillin that he will wear them again in a few moments, upon leaving the restroom. Secondly, if one removes his Tefillin in order to put on a different pair of Tefillin, he must recite a new Beracha upon donning the second pair, since his initial Beracha applied only to the first pair. Thus, for example, if a person could not find his Tefillin and therefore wore the synagogue's Tefillin, and later his own Tefillin surfaced, he recites a new Beracha when he puts on his Tefillin.

Summary: One who removes his Tefillin and puts them back on within a half-hour period does not recite a new Beracha, unless he had gone to the restroom or he now puts on a different pair of Tefillin. If he puts his Tefillin back on after a half-hour period, then in all cases he must recite a new Beracha.