As a general rule, all adults living in an apartment should be named on lease and should be co-responsible for payment of rent and maintenance of unit. This means that each of you is responsible for making sure entire rent is paid each month and that other obligations under lease (maintenance, payment for damages, etc.) are everyone's concern. This also means that you are all protected under terms of lease.

If a roommate is moving in during course of an existing lease, landlord may run a credit check on new roommate, and his or her name should be added to lease. If a security deposit is required, new roommate should pay his or her share.

It is also possible that landlord will require a new lease at a higher rate if a new roommate moves in.

Unless you are covered by rent control or increase is obviously an attempt to prevent additional roommate, he is entirely within his rights to do this.

Payment of Rent

The roommates must agree amongst themselves who is responsible for which share of rent, whether they will pay it to one roommate who pays landlord or if they will pay it individually. This agreement is outside lease, and landlord isn't bound by it nor can he enforce it.

Utilities

As with rent payments, roommates need to agree amongst themselves how utilities will be paid each month, whose name utilities will be in. In my previous roommate situations, I have found it useful to split up utilities, so each roommate has one or more in his or her name. Each roommate is then responsible for paying a share of utilities each month to roommate who receives bill.

Space

The prelims: getting to know your roommate. You should always break ice--it's hard, sometimes, but after you do, you'll be glad you did!

Start with some easy questions like:

What's your family background?

What are some of activities you did during high school?

What are some of your hobbies?

What is your favorite subject in school?

When you first get in touch with your roommate, introduce yourself and share a little about yourself (try using some of questions above for starters). Ask some questions and find out what you have in common.

As time goes on, you and your roommate will figure each other out.

Yes, you will eventually learn what your roommate does and doesn't like, when he or she goes to bed and gets up in morning, how loud he or she is when getting ready to go to class, how many guests he or she likes to have and how often, and so on.

It helps if you can think about how your react to things, so you can tell your roommate what to expect or watch for.