If a surgeon is considering purchasing a navigation system, several factors have to be evaluated including, the planned applications, the equipment already installed, and the specific knowledge of the surgeon. For use in traumatology, fluoroscopy and more specifically 3-D fluoro-based computer guidance is preferable. These technologies are based on intraoperative acquired arbitrary images in contrast to CT-based techniques, which refer to preoperative acquired images that represent a so called "cannel reality". However, image quality has to be considered as fluoro-picture quality depending on the anatomical area (eg long bones, spine, pelvis) and body mass index. CT-based navigation provides better image quality and accuracy but is not able to visualize reduction processes. Therefore personal experience in courses or by on-site teaching is recommended prior taking the decision.