Age-Differentiated E-Commerce Decision Logic: Reviews, Personalization, and Circular Product Acceptance Among Young Adults

Young adults are often treated as a single digital consumer segment, although adjacent age cohorts may differ in e-commerce use and attitudes toward circular consumption. This study compares respondents aged 18–24 and 25–34, and examines whether age cohort or sustainability orientation is more closely associated with e-commerce behaviors and circular product acceptance. The analysis uses a respondent-level dataset harmonized ex post from five separate convenience-sample questionnaire surveys (n = 482 young adults). Respondents were not linked across sources; each hypothesis was tested on the subsample with the relevant variables observed, and the sustainability and circular-acceptance tests draw on n = 179 respondents from two of the five sources. Analyses used Mann–Whitney U tests, Spearman correlations, Benjamini–Hochberg false discovery rate correction, robust ordinary least squares models, and selected ordinal logistic models. Respondents aged 25–34 reported more frequent online shopping, whereas respondents aged 18–24 showed more positive personalization attitudes only before controls were introduced. No meaningful age differences were found in sustainability orientation, ecological purchase willingness, or willingness to buy refurbished products, while sustainability orientation was consistently associated with both circular-acceptance outcomes. The Age-Differentiated Circular Acceptance in Retail E-commerce framework is proposed as a conceptual synthesis: age relates to selected digital routines, while sustainability orientation is a cross-cohort correlate of circular product acceptance. The findings suggest that retailers should prioritize sustainability orientation, product-condition transparency, and risk-reducing information over broad age-based segmentation.