Hello, saw this post will sorting by all communities and new. I'm not an expert but thought I could at least provide advice on where to look for information.

Have you tried looking at articles that talk about marriage and applying them to your situation. As moving in with someone else is a major part of marriage it's likely that many of those points would also apply.

Also, I don't think it's a time thing, I think it's more along the lines of some questions that need to be answered for example:

Are you comfortable putting your financial well being in their hands?
Are you willing to regularly assist with any problems they may have? (stress, mental health, physical health, etc)
Do you share moral/political/religious beliefs?
Are you comfortable with their level of cleanliness?

It's been a while since I've taken a college level interpersonal communications course but I think I remember these questions coming up as things to consider in a romantic relationship.