Why should boundary value analysis techniques be used?

Boundary value analysis technique is used to identify errors that most often occur at the boundaries of input data ranges. This is because state transitions or logic changes often happen at the boundaries. For example, if a function accepts numbers from 1 to 100, testing values 0, 1, 2, 99, 100, 101 helps verify the correct handling of edge cases. This approach allows for an effective reduction in the number of tests while increasing the likelihood of detecting defects.