In my opinion, it is necessary. It filters the incoming water perfectly, without obstructing the flow. It just requires a little attention at the start of washing, until the filter fills up, because air gets trapped inside and may need to be "vented" by unscrewing it for a few seconds, in order to release the trapped air.

Very useful accessory, it is placed externally to the washing machine as an additional protection. Although the water from the network appears to be clean, after each use I see greenness in the filter. This means that if I had not purchased it, all this dirt would go into the motor, resulting in a reduction in its lifespan... It unscrews easily and can be cleaned with water after each use.