The spring balance does not read properly after its long use because

Why does a spring balance show wrong measure after long use?

Why do spring balances show wrong reading after long use ?

A 20 N metal block is suspended by a spring balance. A beaker containing some water is placed on a weighing machine which reads 40 N . The spring balance is now lowered so that the block gets immersed in the water. The spring balance now reads 16 N . The reading of the weighing machine will be.

A 20 N metal block is suspended by a spring balance. A beaker containing some water is placed on a weighing machine which reads 40 N . The spring balance is now lowered so that the block gets immersed in the water. The spring balance now reads 16 N . The reading of the weighing machine will be.

Why do spring balances show wrong readings after they have been used for a long time?