You can do brief "test drives" of living together. Two of my girlfriends recently did this with their long-term boyfriends (serious relationships where there were months before moving in could feasibly happen).

My friend spent a week at her boyfriend's house, acting as if she lived there. A couple weeks later, he did the same, staying at her place for a week. They debriefed at the end to go over what went right and wrong. She raved about this experience, so much that one of our other friends did the same thing with her boyfriend. It was a nice, low-pressure way to identify potential issues early (cleanliness, how chores are divided, sleeping schedules, personal space, alone time) and work through them before the stress of actually moving into a new place.

Anyway, I thought this was brilliant. I wish I had done this with my boyfriend (now-husband)!