When sourcing modular staircases, prioritize structural integrity and material quality. Ensure the stringers (support beams) are made of high-grade carbon steel or SUS304/316 stainless steel with a thickness of at least 6mm to 10mm for stability. For treads, verify that solid wood (such as Oak or Beech) is kiln-dried to a moisture content of 8%-12% to prevent warping, or if using tempered glass, it must be laminated (e.g., 10+1.52PVB+10mm) for safety. Always confirm the load-bearing capacity meets a minimum of 200kg to 300kg per step.