This work explores the potential value of using the enormous amount of activity traces latest ubicomp environments have started to capture. We sought to understand potential practices of using these traces in the long term through a field-based study in the USA that examines how today's people use traces left by their predecessors in the houses where they live.We found that our participants received, discovered, and made use of many small traces held by artifacts, people, and building materials. Those traces were used to provide practical assistance to participants' appropriation of their houses as well as to connect participants with the past in an evocative manner. Our analysis highlights the roles played by the social context and the mutability of the house in the experience of remembering the house as well as in shaping participants' attitudes of passing on traces of prior appropriation of the place. To illustrate the design implications of those findings, we offer three design concepts to characterize potential ways of using traces captured by ubicomp environments in the long term.