Understand that start-ups, scale-ups and more mature companies are completely different animals, regardless of whether you maintain a "start-up culture" as you grow or not. This means that as your company grows, you need different kinds of leaderships and skillsets. The person who successfully leads a company in the first years may not be the leader the company needs as it grows. It requires a complete different skillset to lead an organisation with 50 employees than one with 10. Of course, your leadership & management skills may grow as your company grows, but be honest to yourself and invest in a great leadership team that can help you lead the company. For many entrepreneurs this is a tough decision, but in the end a necessary one. Too many start-ups and scale-ups have failed due to bad/inadequate leadership.