In this paper, we report our findings on the adoption practices of used personal digital assistants (PDAs) to inform reuse of outdated computing products. Our interviews with 12 eBay users who bought used PDAs showed a variety of ways in which users indirectly supported sustainability. This allowed us to re-examine sustainability as something that is dynamically and arbitrarily shaped by the users and not just dependent on the sustainable feature of the product. We end with design implications for supporting users' shaping of sustainability. Author Keywords Sustainable interaction design, sustainability, reuse ACM Classification Keywords H5.m. Information interfaces and presentation (e.g., HCI): Miscellaneous.