well without saves it woud be 17.3 days to be more exact, so the saves add only about one day. But yeah, it is quite a lot of time just for saves.

Just putting this out there, the stream will actually last about 18.2 days because of added time from autosaves, which essentially pause the game. I have the math to back up my conclusion if anybody wants to see, whether it be for curiosity or debate.