These stages are often referred to collectively as the software development lifecycle, or SDLC. Different approaches to software development may carry out these stages in different orders, or devote more or less time to different stages.
There are several different approaches to software development. Some take a more structured, engineering-based approach to developing business solutions, whereas others may take a more incremental approach, where software evolves as it is developed piece-by-piece. There are significant advantages and disadvantages to the various methodologies, and the best approach to solving a problem using software will often depend on the type of problem.