Whether the relationship has been going on for years or you guys seem to have 'clicked' in a short period of time, living together can hugely impact your life and it should be taken seriously. Here are a few things which will help you evaluate if you're ready to take the big step.
1. You have the same relationship goals
Ask yourself why you want to move in together? Is it because your partner doesn't want marriage and this is the farthest they are willing to go, or because you hope to change their mind about having kids, or because you want to keep a closer eye on them; in short if you have any hidden motives and expectations from the relationship then maybe you should hold the decision. You and your partner should be on the same page, having similar relationship prospects. Have a 'talk' with your partner, your 'why you want to move in together' should be in sync with your partner's.
2. You really, really like each other
This one is obvious, you need to have a strong bond even after the honeymoon period. If you are fighting almost every day, you need to figure things out before making the leap. You are set to share a space together if you have built a level of understanding, you accept each other at your better and your worse. You support, love and care for each other and are not in it for all the superficial benefits. You truly know each other and are willing to make efforts because the feelings are too strong, your relationship is not irritable.
3. You have survived a very serious fight
This goes without saying that when you are living together, a little disagreement every now and then is inevitable. If you guys have had one or more of a very serious fight/war, where it seemed like the relationship might end but you got through it together and came out stronger then you know how to handle a fight. It's in these times of conflict when the true strength of a relationship is revealed. So, if you guys have strong conflict resolution skills, know how to solve problems, then you are good to go.