Higher CADR generally means faster air cleaning for a given room size, but it should be matched to your actual room, not maximized. An oversized purifier just runs quieter for the same result, while an undersized one struggles no matter how good the filter is.

Sometimes, but check compatibility carefully. Off-brand filters can fit but use lower-grade filter media, and using one that doesn't match the manufacturer's specs can also void your warranty.

For daily maintenance, yes for most households. Most people still do a deeper manual vacuum periodically, especially along edges and under furniture a robot can't fully reach.

If you have a larger home, multiple rooms, or want to set no-go zones, yes — it cleans more efficiently and lets you target specific rooms. For a small studio apartment, random-path navigation is often good enough.

Manufacturer guidance is a starting point, but actual replacement frequency depends on usage, pets, and local air quality. A visible color change or a noticeable drop in airflow is a more reliable signal than the calendar alone.