For competences development of learners and professionals, target competences and corresponding competence development opportunities have to be identified. Personal Recommender Systems (PRS) provide personal recommendations for learners aimed at finding and selecting learning activities that best match their needs. This article argues that a clear-cut description of the concept of "competence" is needed for appropriate system-based personal recommendations. It is proposed to extend current initiatives on standardization of modelling competences with the concept of "Learning and performance situation" (LP-situation) and it is claimed that this extension has added value for personal recommendations for adequate selection of learning activities, for determining proficiency levels of competences, for the design of learning tasks, and for accreditation of prior knowledge. Advantages and disadvantages are discussed. (Contains 3 tables.)