Recharge and continue where you need it. On a large ground floor, a robot vacuum without this feature requires attention and control to clean the entire area, not my idea of convenience. The i3 can charge and continue without fancy lidars or cameras. And skirting boards on wood and tiles look much cleaner than when cleaning with vertical racks. The overall results are amazing. I vacuumed with my Dyson in an upright position, then started the i3 and was amazed at the improved overall look of the floors. I think robotics has finally met the expectations of big houses.