Geotechnical structures are often partially embedded, if not fully embedded, making it challenging to assess the remaining lifetime and reusability of a foundation. In-situ monitoring offers a solution. By attaching different types of sensors to a foundation, the foundation’s response and reliability can be assessed at various stages of a structure’s life cycle. To illustrate this, an example of a “smart quay wall” is taken from the Port of Rotterdam. During the design phase, fully instrumented pile tests showed that the design could be optimised, leading to substantial financial and carbon emission savings. During construction, movements and forces in the quay wall were closely monitored and were used to validate a numerical model, thus providing a reliable tool at later stages during the quay wall’s lifetime when reuse or readaptation of the quay wall is being considered. Lastly, ongoing measurements during the operational phase of the quay wall have shown a large amount of residual capacity, particularly when compared to the pile load tests.