Paying rent
As joint tenants, you are all jointly and individually responsible for paying the rent. If one tenant moves out without giving notice or is not paying their share, you will be responsible for paying it for them. If none of you pay your rent, your landlord can pursue any of you and ask you to pay the full amount. In practice, they'll probably go after the person who is easiest to find or who has the most money and is more likely to pay. You will also be jointly and individually liable for paying any arrears, even if you personally were not responsible for them.
