> less thorough (lower number of passes over any given spot) If the device is smart enough, thoroughness can be a choice so the user can opt for multiple syste

> less thorough (lower number of passes over any given spot) If the device is smart enough, thoroughness can be a choice so the user can opt for multiple systematic passes instead of being required to wait through multiple random uneven passes. > less robust (navigation easily gets confused by sunlight, dirty sensors, room changes, etc.) This implies that robot vacuums that are sufficiently intelligent don't exist yet.