Praise be to Allaah.
Prayer in relation to the religion is like the pillar or pole of a tent, as the Prophet (peace and blessings of Allaah be upon him) said: “Prayer is the pillar of the religion…”. Prayer has certain conditions, without which it is invalid. These conditions include purity (tahaarah), which means removing major and minor impurities. Minor impurities are removed by means of wudoo’. A person must be pure and have wudoo’ for each prayer, as Allaah says (interpretation of the meaning):
“O you who believe! When you intend to offer As-Salaah (the prayer), wash your faces and your hands (forearms) up to the elbows, rub (by passing wet hands over) your heads, and (wash) your feet up to the ankles” [al-Maa’idah 5:6]
If a person still has wudoo’, and nothing has broken his wudoo’ (the things that break wudoo’ are anything that is passed from the front or back passage such as urine, stools, wind; sleeping; eating camel meat; etc.), then he does not have to repeat his wudoo’. It was reported that the Prophet (peace and blessings of Allaah be upon him) prayed all five prayers with one wudoo’ on the day when he conquered Makkah.
And Allaah knows best.