NIU's KQi scooters are popular for commuter use where predictable range, stable handling, and app features matter. The KQi Air emphasizes lightweight materials, while the KQi3 Max targets longer range-so battery health and charging reliability are the key repair drivers.
For repair vs replace, routine mechanical wear (tires, brakes) is normally worth fixing, especially if the scooter is still relatively new. If the main issue is a controller or charging port and the total repair is below the threshold, repair is typically reasonable.
Replacement becomes more attractive once you have meaningful range loss plus another major fault (controller/display), or if the scooter has repeated water-related electrical problems. Pricing referenced from NIU's KQi3 Max product page and NIU Store pricing for the KQi Air line used to set a representative "today" average.