Someone asked me for advice on living with a flatmate or roommate. What questions should one ask in advance to ferret out and defuse potential problems? I have a list. It's huge. Unfortunately, some questions require metacognition in the interviewee.

• How will we divide expenses for rent, food, electricity, gas, water, garbage, cleaning products, and plumbers?
• Who will be on the lease? Will we pay rent to a master tenant or to a landlord? Who will interact with the landlord? How is the landlord?
• When you leave the house, do you turn off all the lights before you go? How about when you go to sleep?
• Which locks do you like to lock when you are at home alone? Or when you leave?
• When you experience stress, how do you react? Do you take it out on other people, or stoically deal with things yourself, or share your concerns?
• Do you want me to be a friend or just a flatmate? Will you depend on me for all your social activity? Are you generally outgoing or introverted? If you are not very talkative with me in the kitchen or living room, does that mean you are unhappy with me?
• Do you prefer to keep separate stores of food or to share all food communally? How would you prefer to split food costs? How often do you like to cook meals at home, and do you think cooking meals counts as much as buying the ingredients? What are your dietary restrictions? Will our separate diets come into conflict?
• How much reminding do you need from a flatmate to do something you don't want to do? How many reminders to do a chore do you feel comfortable giving a flatmate?
• How much TV do you like to watch every night or week? How about rented movies? Do you like to keep the radio or TV on as background noise when you are doing something else?
• How much of the common area will you want to fill with your stuff? How about storage closets?
• How often will you have friends over? How many friends do you like to have over at once? When is it necessary to inform your flatmates in advance, or apologize? How far in advance should flatmates tell each other about parties they are planning to throw, or about visiting friends who will stay and sleep in the apartment? When is notification enough and when is consent necessary?
• Do you get annoyed when your flatmate has friends over and doesn't want to converse with you?
• When do you like to use the bathroom and shower in the morning and evening? How long are your showers? Do you ever take baths?
• Do you like to keep your bedroom door open or closed when you are inside? How about when you leave the house?
• How do you deal with mail for your roommate? How about phone calls and messages?
• Do you think of yourself as a neat person or clutter-friendly? How often do you clean the bathroom? clean the living room? do dishes? do laundry? clean the kitchen? What does "cleaning" mean and entail? How should we divide these chores?
• What hours do you sleep during the week? on the weekends? Are you a light or heavy sleeper? When should we have quiet hours?
• What are your computer habits?
• How often do you date? Are you planning on bringing anyone over to have sex or sleep over? Should flatmates tell each other in advance if they anticipate bringing a date home? Is it okay to have sex with a date when your flatmate is home?
• What do your religious beliefs or political beliefs say about how we should live at home? What will you proselytize me about?
• What are your politics?
• Do you enjoy shopping for clothes? for books? for groceries?
• How loud is appropriate for music in the common area? in the bedroom? What kind of music do you like?
• What posessions and areas are private?
• Do you have a car or bicycle or motorcycle? Should we share any of these things?
• There is a dirty cooking vessel in the kitchen that you did not soil. Do you wash it when doing the dishes? Is it okay to use someone else's dishes or pots without asking first?
• You damage your flatmate's possession accidentally. What do you do?
• Do you prefer for common areas to look spare and Scandinavian or cluttered and cozy?
• Do you want your home to be a place to socialize? to study? just to sleep?
• Are you a miser or a spendthrift?
• Have you lived with other people outside your family before? How well have you gotten along with flatmates in the past? Can I speak to a former flatmate of yours?
• Why do you want to live with me/move? How long have you lived in your current home? How long will you want to live with me/here?
• Do you think you are easy to live with?
• What are your questions for me?