How do you feel about modifying already completed tasks and refactoring?

Modifying already completed tasks and refactoring are an integral part of professional development. They allow improving code quality, increasing readability and maintainability, as well as adapting solutions to new requirements.

Refactoring helps eliminate technical debt, improve architecture, and simplify the addition of new features. It is important to approach this systematically: make small changes, test them, and not break existing logic.

Example in Java:

// Original code
public int sum(int a, int b) {
    return a + b;
}

// After refactoring: add null check (if parameters are objects)
public Integer sum(Integer a, Integer b) {
    if (a == null) a = 0;
    if (b == null) b = 0;
    return a + b;
}

Thus, refactoring is not just code modification, but an improvement of its quality and adaptation to new conditions.