I'm only looking to do my living/dinning room and hallway. I would say that area is 350 to 400 sq ft. The carpet is not in that bad of a shape, I do have a dog and a young child so that does not help in keeping it clean. I have a few spots that look like it could be oil based. I think what happened is I might have vacuumed up something that was wet and lube or oil from the vacuum cleaner got on the carpet. I have tried to get it out a few times with no luck.