I wouldn’t even consider finances. What would someone do if he/she was single, and needed to support him/herself? I don’t think finances are ever reasons to move in together–there really is no reason to move in together, unless one is married. This is my opinion–it just causes a near occasion of sin, and tempation.
I also have known friends who have done this, moved in together for financial reasons, and then they married, and I think they wonder if they married for the right reasons. I think it becomes a matter of convenience for many, to get married simply because they have lived together for a while.
The stats don’t lie, also–people who live together before marriage, tend to undergo higher divorce rates, than people who wait until marriage to live together. Not to say people can’t have forever marriages who have lived together, but statistically speaking, the rates of divorce are just higher for those who chose to live together–for whatever the reasons–before marriage.
Just my thoughts.
So, yes, I’d live in a separate residence if I wasn’t married.