Changing the water tank after a number of years, in general 5-10 years, is a wise decision as the tanks rust and limes together.
The more lime, the more energy is used to heat the water. Calcium is found naturally in water and precipitates when heated at temperatures above 58 degrees, it will then drop to the bottom of the tank, covering the element. In the worst of cases, the thermostat will break and the tank begins to boil, which can lead to water spraying onto the floor through the safety valve underneath. Alternatively, the RCD will break and there will be no hot water - then it is high time to replace the tank.
We use water tanks of high quality from known suppliers and when we change the tanks we also change the hoses.