Awhile ago I worked out that, if you want to watch a different disc every evening using Netflix, your quota (the number of discs you have out at a time) needs to be at least five: three for the mail cycle plus two because Netflix does no processing on Saturday or Sunday. (This assumes no glitches and no holidays. It also assumes you do not get the disc back into the mail on the same day you received it.)
Now I see that Netflix has begun working on Saturdays, reducing the addict’s minimum quota to four. That means they’ll get $6/month less from each subscriber who applies my reasoning. Hm.