The first robot vacuums might be realized sooner if their designs sacrifice some efficiency for robustness achieved by persistence, and if they can expect reasonable cooperation from the household. In many houses, there are times when each room is unoccupied long enough to permit its being vacuumed without disrupting normal family life. Sacrificing sophistication to achieve minimal competence earlier, RoboVac version 0.0 might operate only in "vacuum-proofed" houses. Similarly, early versions of RoboVac need not sweep the room with maximum efficiency if the room is vacant for reasonable stretches of time. Over time, RoboVac should increase its efficiency by learning the house layout and the best times to clean each area.