To match resistance value

In series connection, the recommended resistance range is with +/-5%; in parallel connection, it may be +/-10%. In the case of an element that has failed or broken in a short time frame, replace it with anew element. It's better to choose an element with higher resistance. If an element is used for a prolonged time, all the elements in a group have to be replaced; otherwise, the new or old element will be subjected to too high a load and will fail prematurely.