How long do angels live for?
There exist two types of angels, one called Beni Elokim, and the second called Bnei Eilim. The angels of Bnei Elokim, are angels that were created during the six days of creation, and they do not die or expire. They have been serving G-d since that time without fail. The second type of angel, Bnei Eilim, is angels with a lifespan of a mere few hours. They are created daily, in the morning, for the purpose of singing praise to Hashem, and expire within this process of singing. These two forms of angels are hinted to in the daily prayer of Birchas Shema in which we recite “Veyotzer Mesharsim Veasher Mesharsav”; the term Yotzer Mesharsim refers to the angels that are created daily while the term Veasher Mesharsav refer to the angels that live forever. The temporary angels derive from the level of Desha, which means plantation, as they are similar to plants which grow daily from the earth. These angels of Bnei Eilim are the angels that are found in the world of Assiya.
 Likkutei Torah Pinchas p. 79b