This is probably a dumb question, and I'm not even sure I know how to ask it (I sure didn't know how to search for it!) I've noticed that the updates for my Mac are have kind of large file sizes x the number of times it updates = lots of memory used. How is this handled? If I download an update, does it write over whatever it's updating and then toss itself out? How does this work? Do I need to do anything or will I one day have noting but OS? Am I making sense?