Sometimes, if you have the hammer and a chance to score 1, you will choose to clear the house and not score any points, so that you can keep the hammer and aim for a bigger score in the next end. Oh, so going last isn't a rotating thing, but rather a who didn't score last thing. Correct. Another reason you might do it is to make sure you have the hammer in the decisive end. If the other team is sitting the only rock in the house and you have the hammer in the 9th end of a tied match, you might choose to clear the house so you can be tied with the hammer going into the last end, which is a dominating advantage.