The diversity of flora and fauna in the world has evolved over time by passing on key information in DNA. Retaining knowledge therefore allows organisms to 'learn' from the past. We also must learn to retain knowledge, so that we can learn from our past successes and failures. We retain knowledge in our memories, and this process becomes more efficient when those memories become tacit and deep-rooted. So over time, as we learn to drive for instance the process becomes routine and automatic. This frees up valuable congitive resources for dealing with new problems and situations. Knowledge can thus be habitualised through practice. It can be further routinised as it is embedded in the collective actions of groups of individuals. However, there is a note of caution here. While retained and routinised knowledge can allow us to build on the experiences of the past, it can also constrain our actions into behavioral ruts. The more we used retained knowledge, the more automatic it becomes and with this the more resistant to change. Exploiting our past experiences can thus prevent us from exploring new futures.