For many people this is enough, and will often be sufficient to maintain the level of skill and knowledge necessary to fulfil their current role or to move into similar roles if they wish. However, if you are at a stage in your career when you need to learn new skills or do a lot of learning, whether to understand a new sector, to cope with dramatic change, or for a different role, then you might need to take a more structured approach to ensure you develop all the competence you need as quickly as possible.
A structured approach means that you identify the specific skills or knowledge that you need and formulate a plan to achieve them. You will also need to regularly review your progress to assess whether you have achieved your goals, and maybe to plan some further development. This process is called the development cycle.
If you work in an organisation that conducts appraisals or has a formal training scheme then some of this will be done for you; but you may still like to keep personal plans and records to meet your own needs.