What pupils learn in school should ideally be useful throughout their whole lives. It should help them in further studies, in working life, and when acting as responsible citizens in democratic society. This is challenging for all subjects, including technology. Technology develops fast. It is most likely that wheels, wedges, and inclined planes will be used in the future, but it is difficult to know which programming languages, sources of energy, and materials that will be relevant a few decades from now. This article describe how these problems are handled in international curricula and standards, and by Swedish teachers, teacher students, and teacher educators. In curricula they are seldom addressed explicitly, but handled by giving deliberately vague descriptions of what students are to learn. The interviewed teachers, teacher educators, and teacher students were unused to think about future-compliant or timeless knowledge. When prompted to do so during the interviews, they found it easier to describe timeless skills than timeless factual knowledge. Prominent among their suggestions were abilities related to engineering design processes, technical problem solving strategies, fundamentals of computer programming, and engineering mechanics.