Before moving in with a best friend, you sit down and think about all the reasons you would and wouldn’t make good housemates. You think about what changes you’ll have to make in order to keep the peace. You think about what quirks of theirs you’ll have to become more comfortable with. For some reason, couples don’t give that much attention to detail when considering moving in together. Fusing your life with somebody else’s will never be seamless, but mentally preparing yourself for the change can help fend off that panic moment of, “Ah! What have I done?!” So, be ready for this.