Operating temperature is the first consideration. Because the temperature is too high will cause the magnet to lose its magnetism.
Second, the required magnetic field or pulling force.
Another factor to consider is the size and shape of the magnet. If the shape is too complicated, it will increase the processing difficulty.
Also, you should consider the corrosion resistance of the magnet. If the magnets are to be used in wet, acidic or corrosive environments, suitable protective measures such as coating or wrapping need to be selected.
Finally, cost is also an important consideration. The price of NdFeB magnets with different sizes, shapes and performances varies greatly. You need to balance the performance and cost of the magnet according to your budget and application needs, and choose the option that suits you best.