We, humans, gain experience by doing something for a prolonged period. In this paper, we address whether we can link the use of advanced language features in software to a greater developer experience, indicating higher software quality. The coding style we chose to measure is the usage of lambdas and whether it correlates with programming experience since previous research has shown that less experienced C++ developers face difficulties with lambdas despite them being a language feature for almost ten years. If we established that lambda use and developer experience correlate positively, we could further investigate whether a good understanding of lambdas has a lasting contribution to software quality. Further, we could use it as an indicator within code quality metrics and promote the teaching of functional programming and lambda use in software engineering curricula. To measure experience, we introduce the Mean Repository Experience (MRE) metric, a novel but straightforward way of measuring what we here call repository experience, i.e., the combined assessed experience of contributors in a repository. We use this metric to analyze 500 C++ repositories. The proposed MRE metric shows potential as a proxy for software quality and could further extend to advanced language features other than lambdas. Our results suggest that the developer experience positively correlates with lambda usage. Future research includes understanding how well MRE reflects actual developer experience and further implications.