Selecting the right expansion joint depends on the movement requirements (thermal, seismic, or settlement) and the application area. For floor-to-floor joints in high-traffic areas, prioritize heavy-duty aluminum profiles with recessed covers to maintain a flush surface. For exterior walls, ensure the system includes a primary water seal and a secondary moisture barrier to prevent water ingress. For roof joints, UV-resistant EPDM or Santoprene seals are essential to withstand extreme weather conditions.