Praise be to Allaah.
There is no option when it comes to doing obligatory actions, because Allaah has enjoined them upon us. The same applies to abstaining from haraam things. There is no sense in praying istikhaarah concerning matters which we have no choice about doing. Salat al-istikhaarah was not prescribed for this purpose. Istikhaarah is for permissible matters where one needs to choose the better of two options, or when one has many permissible options. So one prays istikhaarah in order to choose one particular permissible thing, when one is confused as to which city to go to in order to seek knowledge, or which shaykh one should study with, or which halaqah one should attend. So you consult people, then you pray istikhaarah concerning the one that you think is more likely to be better. Similarly, you pray istikhaarah when you plan to propose marriage to a specific woman, or when deciding whether to do a naafil Hajj this year or next year, or when deciding about any matter in which there is hesitation (between choices). This is what is referred to by the words “He taught us to pray istikhaarah in all our affairs.”