Maintenance work, executed by mechanics, electricians, welders and other tradespeople, is imperative for industrial equipment to operate as planned. To ensure high standards of work and safety, maintainers are required to comply with procedures that specify how tasks should be executed. In the past these procedures were paper-based but they are increasingly available digitally in the field on tablets and other devices. Maintainers work in variable and often challenging environmental contexts. The same work can be done inside a shop or in the field, day or night, cramped or open conditions. Often there is just one version of a procedure although one maintainer may have 30 years experience and another only 3 years. Additionally, maintainers themselves have individual differences resulting in different aptitudes for technology. Therefore, maintenance procedures are a suitable use-case for Adaptive User Interfaces (AUI). In this paper, we define six high-level requirements for an AUI for maintenance procedures and discuss opportunities for future research, particularly in the space of multi-Target AUIs. This work is in its preliminary stages and could benefit from early discussion with the Human-Computer Interaction (HCI) community.