When is the renewal of ablution for the next prayer performed: Is it before the prayer's time begins, or when its time begins? And is performing the two rak'ahs of ablution before the time of Maghrib begins valid and legislated?

It is recommended to renew ablution for an obligatory prayer due to what Al-Bukhari narrated from Anas ibn Malik, may Allah be pleased with him, who said: "The Prophet, peace and blessings be upon him, used to perform ablution for every prayer." Scholars differed regarding the criterion for renewing ablution. Some said it is recommended for one who has prayed with it (obligatory or supererogatory prayer), while others restricted it to obligatory prayers only. Some extended it to include anyone who performed an act permissible only with ritual purity, such as touching the Qur'an. Others said it is absolutely recommended, even if nothing was done with it, provided that a period of time intervenes between the renewal and the previous ablution. No scholar stipulated that the time for the next prayer must have begun for ablution to be renewed. Therefore, it is permissible to renew ablution whenever you wish, whether before or after the time begins.