In recent years, I have been developing new propositions and introducing existing propositions to new markets. A common problem is that many startups fail and existing propositions do not become successful in new markets. But why? The reason for this is that too much is done based on assumptions and even in some cases on pure luck. Entrepreneurs seem to know in advance why their proposition will be a great success, despite there is no urgent or big enough problem to solve. And having a proposition that is successful in one market does not automatically make it successful in another market. Working based on assumptions increases the likelihood of failure. Under the name Founders and Builders, I engage with founders of startups and scaleups to learn from their successes and fuckups. Primarily to learn from them myself. But I don't want to keep their secrets for myself. Therefore, I will share them with you so that their insights are the inspiration for you to become even more successful. After reading these blogs you will know the do's and don'ts of entrepreneurship.