If we had given zakat for particular things (money, gold, property, etc) for a year and if the value of the things didn’t increase during next year and do we need to give zakat?

The mere possession of liability free assets, money, gold, property etc.
equivalent or more than the minimum zakaatable amount is a cause for the
obligation of zakaat. The increase in its value is not necessary.
Therefore, if one discharged zakaat on his/her assets the previous year, it
has to be discharged again even though the value of the assets did not
increase. Apart from the above, all the other laws of zakaat must be taken
into consideration in fulfilling the obligation of zakaat.

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai
FATWA DEPT.