[FONT=Verdana][SIZE=2]…the wealthy according to his means, and the straitened in circumstances according to his means. The gift of a reasonable amount is necessary from those who wish to act in the right way.' (2:236).[/SIZE][/FONT][FONT=Verdana][SIZE=2]In a famous case, the second Caliph, Umar b. al-Khattab, once gave a public sermon in which he asked the congregation to refrain from fixing heavy mahrs, and stated that the Prophet had declared no-one should give more than 400 dirhams. A woman immediately stood up and challenged him, quoting the verse 4:20 from the Qur'an: 'But if you decide to take a wife in place of another, even if you had given the first a heap of gold (quintar) for a dowry, you shall not take the least bit back.' Umar went back to the minbar and withdrew his words stating 'the woman is right, and Umar is wrong. Whoever wishes may give as much property as he wishes to give.' (Ibn Hajar al-Athqalani, Fath al-Bari, 9:167).
also, there is no requriement, it be paid at one time.. it is acceptable to set up payments to the wife, for this.
[/SIZE][/FONT]The second way of presenting mahr is to defer it, to hand it over to the bride after a certain period of time, the duration of which must be specified, fixed by the man and agreed by the wife. This has to be settled, with witnesses, at the time of the marriage. This form of mahr is known as mahr muwajjal. (the word implies 'in a period of time').