Startups are always in the hassle of saving costs and optimising the rates of every service they get. Software development can be one of the most expensive services startups can buy, and in many cases, outsourcing is definitely the wise choice.
Outsourcing the development of custom software can be a wise decision, as you avoid the much technical hassle that can come with it. When you decide to choose a company for this, it will be like outsourcing anything else. Many choices and tens or hundreds of companies offering the same service.
Underestimating software development risks is a big mistake. Management of a software development project, and is responsible for it is not easy. Many different challenges can also show up while working on software projects. It depends on the type of the project, the technologies used, and the management methodologies.