Cross-cutting concerns are aspects of a software system that affect multiple components but are not limited to a single module. Examples include logging, security, and error handling. These concerns can complicate the design and maintenance of software because they require attention in various parts of the system, leading to code duplication and increased complexity. To manage cross-cutting concerns effectively, developers often use techniques like aspect-oriented programming or middleware. These approaches allow for the separation of these concerns from the main business logic, making the code cleaner and easier to maintain. By isolating cross-cutting concerns, developers can enhance code reusability and reduce the risk of errors.