Plog's psychographic theory was developed to analyse tourist behaviour. The present study examines this theory as Plog's psychographic theory reaches its 50th anniversary. Replication is one of the most acceptable ways to assess scientific quality and reliability. Using categories of replications, the study systematically screened the citations of Plog (1974, 2001, 2002) from the Scopus database (n = 1185) of referred academic works and analysed its 34 replications (1991-2023). The findings of this consecutive replication analysis showed 23.5% support for Plog's theory alongside various validity and reliability issues in replicating papers. The segmentation of people was found to be relatively more replicable. Based on these findings, four lessons for tourist behaviour scholars were set: to adopt updated theories and perspectives, maintain and report reliability measures, conduct replication studies, and borrow data but not models from practitioners.