Sometimes a fresh look from the outside can shorten many hours of development. Before expanding staff and hiring developers, you can order a code review to detect problems in the code. Effective refactoring can eliminate many bugs and increase system speed. I understand that each system is unique and is a trade secret. It is enough to analyze a part of the code, for example, one or two modules, to evaluate the style of work and determine the points for correction. Or get the answer that your system does not require a significant changes and you have assembled a really great team