Similar to setting expectations about how you use shared space, it's important to plan for other rules and expectations. How will you divide up cleaning? What other chores and responsibilities will you share?

Are the things in the kitchen like pots and pans communal, or will you each have your own? Some foods may be easier to share than having separate, such as spices. If you will all use equal amounts of something and want to share it, how will you decide who buys it? It might be a good idea to rotate purchasing.

Things like toilet paper, cleaning supplies, and other such products probably need to be communal. That said, how will you share responsibility for them? Do you have expectations about what products you buy? Someone might have a preference for specific products, while others might prefer to choose based on price.

Make sure you are on the same page on the division of cost and shared items with your roommates before you move in.