Under-sink water purifiers do not need frequent replacement of water sources. Once installed, the under-sink water purifier typically remains connected to the household water supply and automatically filters water as needed. Therefore, households do not need to frequently change water sources. The water purifier will continue to provide safe and healthy drinking water, requiring only periodic replacement and maintenance of the filter cartridge to ensure filtering effectiveness and longevity. Depending on the brand and model of the water purifier, the replacement cycle for the filter cartridge may vary, and users should follow manufacturer recommendations or actual usage conditions for operation. Overall, the use of under-sink water purifiers is convenient and long-lasting, without the need for frequent replacement of water sources.