According to Shulchon Aruch, a person who removes his tallis must recite another brocha when he puts it back on. This is true even if he planned to put it back on again after he took it off. However, if he had this plan in mind at the time he originally made the brocha, a new brocha is not necessary. Although some opinions disagree with the Shulchon Aruch, it is appropriate to have this intention in mind when first reciting the brocha so that all opinions are satisfied. If a considerable amount of time passed before the tallis was put back on, this solution is no longer effective and a new brocha is necessary. The poskim offer various opinions on how much time must go by before a new brocha is required.
[שו"ע ח, יד, משנ"ב לו, וביה"ל ד"ה אם, וד"ה ויש; ביאורים ומוספים דרשו, 52 ו־54]