Those who said: zakah is taken only once a year

Al-Zuhri said: It has not reached us concerning any of the rulers of this Ummah who were in Madinah — Abu Bakr, Umar and Uthman (may Allah be pleased with them) — that they collected zakah twice in a year. Rather, they used to send (collectors) every year, in times of plenty and of drought, so that it would be collected from the people according to the Sunnah of the Messenger of Allah (peace and blessings be upon him).

Tawus said: When two charities (two years' dues) fall together, do not collect the first one, like the jizyah.

It is narrated from Fatimah that the Prophet (peace and blessings be upon him) said: "Zakah is not to be taken twice in a year."