Is it permissible to make a vow to pray two voluntary rak'ahs between the 'Asr Adhan and the Iqamah for life, and does that affect the performance of other Sunnah prayers?

Many scholars disliked vows, especially conditional ones, because they do not avert anything and are used to extract from the miserly. The dislike intensifies if the vow is repetitive, due to the potential hardship, boredom, and failure to fulfill it. However, the vow must be fulfilled if its condition is met, as Allah Almighty says: "And let them fulfill their vows," and as the Prophet (peace be upon him) said: "Whoever vows to obey Allah, let him obey Him."

Therefore, this person's vow is considered a vow of obedience that he must fulfill every time he prays between the adhan of Asr and its iqamah. He should pray two rak'ahs afterward to fulfill his vow, and he is not permitted to delay them beyond their designated time except for a valid excuse.