Is the prayer of Istikhara (seeking guidance from God) established in practice?

Primary text

The practice of Istikhara in all matters is established by the precedent of the Messenger of God, peace and blessings be upon him. He taught it to the Companions just as he taught them a chapter from the Quran. The procedure requires the supplicant to perform two non-obligatory units (rak'ah) of prayer. Following the prayer, the specific supplication must be recited, which includes affirming God's knowledge and power, and requesting benefit from His great bounty. The supplication explicitly requests that if the matter is good for one's religion, livelihood, and final outcome, it should be decreed, facilitated, and blessed. If the matter is ill for the same aspects, it should be turned away, and the supplicant turned away from it, with good decreed wherever it may be, and contentment granted therein. This is based on the Hadith narrated by Jabir ibn Abdullah al-Ansari, narrated by Al-Bukhari.