How often should tenement rate be increased?

[btaliat]

There is always urge for the landlady and landlords to increase the money paid by their tenants. There are many reasons why this many be so. Some of the reasons why this may be so is that houses do appreciate especially if the landowners have renovated their houses.

Some other factors may be if the government just provide some social media or may be some big establishments, like universities and many more. This can be a sole reason why tenant may want to increase their tenement rates.

But if I may ask, for how long should a landlord wait before he increases the tenement rate?