Collaborating with others on new works can be a fruitful and beneficial experience in the creation of a work, however collaboration without a prior agreement set in place can turn a once friendly and well-intentioned project into a tricky and costly litigation.
A large fraction of those trying to obtain intellectual property protection over their works collaborate with others without an agreement in place, which quite often leads to a costly dispute down the road. Ensure that your work, whether it is created individually or through a collaborative effort, attributes ownership accordingly as you seek intellectual property protection over it.