The present study explores the under-researched area of collocation use with learners from different proficiency levels. The study investigates different types of collocations and the learners' elaboration of their collocation use. A total of 194 students from three different years of study in a Chinese university wrote compositions on the same topic, and 42 of them were invited to post-writing interviews on collocation use. The compositions were used to retrieve collocations, and the interviews to explore each learner's reflections on collocation use. The results showed that learners fail to demonstrate consistent improvement in the use of collocation in terms of frequency and association strength. The overwhelming majority of the collocations in learner writing are below the MI threshold. The present study also found that learners at the advanced stage of learning need both awareness for collocations, and more importantly, awareness for low-frequency collocations with high MI scores.