The expertise approach (Ericsson 2008) has been used to explore the competence of translators and interpreters since the mid-1990s, and is now a well established sub-field in translation and interpreting process research (Jääskeläinen 2010). In the area of interpreting, Ivanova (1999), Liu (2001) and others have explored the expertise approach. The studies reported in this article follow up on this work, but go one step further and investigate both process and product. The aim of the two studies was to explore the differences in performance between interpreters with shorter and longer experience (possible experts). Participants (n = 9) with no, short or long experience interpreted the same speech and performed retrospection immediately after. The first study, dedicated to process, used Ivanova’s (1999) method for investigating the process. The second study, on product, let two groups, non-interpreters (n = 6) and interpreters (n = 6), rate the interpreting performances using Carroll’s (1966) scales for intelligibility and informativeness. It was found that the degree of experience influences the processing strategies used by interpreters and the types of problems they report. Experience also has an impact on how the product of experienced interpreters and that of less experienced interpreters is rated, both when rated by interpreters and by non-interpreters.