This has to be one of the first questions that an entrepreneur asks themselves before committing to an idea or venture. Successful start-up are usually based on filling a defined customer need or providing a solution to an existing problem. The need itself doesn’t have to be basic; it can be based on fashion or social trends, but your solution has to fill an existing gap. It is eminently more difficult to start generating cash flow and raise capital based on the assumption that demand will follow supply. Forging new markets is noble, but generating cash flow from existing ones speaks louder to investors.