According to Hazrat Jabir Bin Abdullah Razi Allah Anha, our dear Prophet Mohammad (SAW) used to teach the method of performing an Isteqhara with the same earnestness with which he used to teach the verses from the Holy Quran.
Since an Isteqhara is a way of seeking guidance from Allah therefore Huzur (SAW) has described those people as unfortunate who do not follow this method to obtain guidance from Allah.
Hazrat Saad Bin Waqas Razi Allah had revealed a saying of our Prophet Mohammad (SAW) that “It is the righteousness of people to perform Isteqhara and their misfortune if they do not do so. Moreover, those people are fortunate who follow the guidance they get from Allah through an Isteqhara and the ones who disobey Allah’s guidance are considered to be unfortunate.
It has been mentioned in a Hadith that Prophet Mohammad (SAW) has said that the person who performs Isteqhara will never be unsuccessful. Moreover, such a righteous person may never have to repent about any of his actions.