Originally Posted by CPRich

I rarely had SPG issues, but that's nott really the topic/question asked here.

In practice, the requirement is typically that you have housekeeping service every third night. So in groups of three nights you get 250, 250, 0 points, rinse and repeat. You can't skip housekeeping on your last night, so for a 20 night stay you would receive 500 points each for 6 sets of 3 nights, 250 for the 19th night, and nothing for the last night, or 3,250 points.