When evaluating an electric stair climber, the most critical factor is the Load Capacity, which typically ranges from 70kg to 500kg; ensure the model exceeds your heaviest anticipated load by at least 20%. You must also verify the Battery Type and Endurance, prioritizing Lithium-ion batteries for their lighter weight and longer life cycles (typically 800-1200 steps per charge). Additionally, check the Climbing Speed adjustment (usually 20-40 steps per minute) and the Motor Power (brushless motors are preferred for lower maintenance and higher efficiency).