Over the past three years, we collaborated with Swedish industries to explore how Augmented Reality (AR) can support production workflows in industrial manufacturing environments. This paper reflects on the design, development, and testing of AR prototypes for head-mounted optical see-through displays in real-world industrial settings. We investigate AR deployment across four manufacturing contexts: house production, inspection, tool change, and changeover operations. Through iterative prototyping and cross-case analysis, we identify recurring usability and integration challenges and extract corresponding user needs. These insights inform a set of design guidelines for AR in industrial production.