Is a person's saying to himself, "I will fast every Monday and Thursday," considered a vow (nadhr), especially if he is unaware of the conditions for a vow? And what are these conditions?

A vow is not established by self-talk or mere intention, for the Prophet, peace and blessings be upon him, said: "Indeed, Allah has pardoned for my nation what they talk to themselves about, as long as they do not act upon it or speak of it." Similarly, uttering "I will fast every Monday and Thursday" does not obligate anything, as it does not convey commitment.