Any application that we build should be assessed in terms of object-oriented best practices. Robert Martin published what is known as the SOLID design principles, which is an acronym for five different object-oriented best practices. Following these practices will help to ensure that the code we write is easy to maintain, easy to understand, easy to extend, and resilient to change. In our current fast-paced world, we generally don't have the luxury of taking extraordinary amounts of time to modify our applications in order to keep up with ever-changing requirements. The faster we can deliver updates to satisfy our business needs, the better chance we have of keeping ahead of our competition. Sticking to the SOLID design principles gives us a good foundation that will easily enable modifications to existing code in order to satisfy these rapidly changing demands on our code base.