@steve babiak mentioned the joint and several clause in another post and it seemed like a good topic to discuss.

if you don't have this clause in your lease I would strongly recommend it. Here is a definition for tenants. If an agreement states that you and your roommate(s) are "jointly and severally liable," it's confirming that you're individually and collectively liable for the entire rent. In the event that your roommate(s) fail(s) to pay, you can be held responsible for his/her portion of the rent. This "joint and several" liability continues throughout the stated life of the contract.

An example from landlordology - Each Tenant(s) is jointly and severally liable for all Lease Agreement obligations. If any Tenant(s), guests, or occupant violates the Lease Agreement, all Tenant(s) are considered to have violated the Lease Agreement. Landlord’s requests and notices to any one Tenant(s) constitute notice to all Tenant(s) and occupants. Notices and requests from any one Tenant(s) or occupant (including repair requests and entry permissions) constitute notice from all Tenant(s). In eviction suits, each Tenant(s) is considered the agent of all other Tenants in the Premise for service of process. A notice to vacate must be signed by all Tenant(s) or it will not be considered valid.