Can you tell about your experience using custom exceptions in real projects?

In one of my C# projects, I created custom exceptions for more precise error handling related to business logic. For example, to validate user data, I defined a ValidationException class that inherits from Exception. This allowed centralized validation error handling and providing clear messages to the user.

Example:

public class ValidationException : Exception
{
    public ValidationException(string message) : base(message) { }
}

// Usage
if (string.IsNullOrEmpty(userName))
{
    throw new ValidationException("Username cannot be empty.");
}