H-clips are not required on all roofs, only those roofs for which they are specified by the architect, engineer, or building code. Lack of H-clips is a deficiency only if they were specified but not installed. Typically, home inspectors will have no way of knowing whether they were required.

H-clips are installed between rafter or trusses to provide added support to panel edges, not to create expansion gaps, since panels are actually in direct contact with each other wherever an H-clip is installed.