If the time comes when you're going to be renting a home, you might wonder whether you'd be better off signing a formal lease or simply entering in to a more casual tenancy arrangement. Of course, the decision may be out of your hands — your landlord may insist that you sign a lease (this is almost always the case in an apartment building, for instance). Tenancies for a period of more than three years must be in writing; if you're simply renting a basement apartment in someone's home, however, or doing something else along those lines, you may not have to sign a formal contract. It's good to know, though, just what the advantages and disadvantages of a formal leasing arrangement are.