SummaryThe aim of this investigation was to study intra‐assessor reliability and the relationship between individual and simultaneous evaluations when retention and stability of complete prostheses and the condition of the residual ridges were clinically assessed according to defined criteria. Further, inter‐assessor reliability and the reliability of simultaneous evaluations were studied by evaluating the condition of the residual ridge on two occasions. Nine patients and three prosthodontists participated.Generally, the reliability levels were low and individual deviations from the simultaneous evaluations were com