All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is recommended for a slave of Allaah to make Istikhaarah if he is hesitant about doing something of the worldly affairs which are permissible, or if he is hesitant about choosing between two things that are permissible in origin. Istikhaarah is not necessary for affairs which are obligatory or recommended to fulfill, since we are commanded to perform them anyway. Making Istikhaarah about doing something prohibited or disliked is invalid also, since the slave is commanded to refrain from such actions anyhow.
There is no blame on a person who makes Istikhaarah in order to choose between two things about which he is hesitant, and then he settles for a third choice. An example of this is the case of someone who is hesitant about buying any of two houses and makes Istikhaarah about this, and then he buys a house other than these two. Perhaps Allaah Almighty chose that which is better than what he thought about for him.
Allaah Knows best.