Projects with an estimated maximum development duration of a month can easily be accomplished in an agile developement method. Sometimes developers are over amiguous and disregard the advantage of a classic software engineering. The classic software engineering is an art in itself and not everybody studied it, so be careful who advices you. Time to market, return of investment, therefore financial risks have to be taken into account for developer and customer. Without a professional advice respectively software specifications, deadlines can not be trustworthy. Usually a project that takes around 3 month and more to develop, needs a software specification, respectively requirements analysis. In 2021 there is an unbelievable variety of opensource, including top class code developed by the smartest people in the world. These codebases can be complex to handle. To choose a technology is the quest being discussed in a software specification.
Sometimes a highly skilled coder can program a tool faster than searching for it and testing the opensource solution. In applied computer science in the meanwhile, it is rather about to know which library to use, than to be able to develep high class libraries, which in between the 1980 up until 2010 has been a task to also set standards. There are a lot of big players, who wanted to found a Business Class Lobby. What moves the world the most is Cloud Computing these days respectively IoT. Just a couple of years ago Business Solutions were coded in heavy to handle, rigid Frameworks which are being replaced now by cloud solutions, cross compiled and delivered to respective Operation System.