ORS 91.210: Rents payable in advance unless otherwise agreed; demand unnecessary.

Unless otherwise expressly provided by the lease or terms of holding, all rents reserved under the lease or terms of holding are due and payable in advance. The tenant shall pay or tender payment thereof on or prior to the first day of the rent paying period provided in the lease or by the terms of the holding, and no demand therefor is necessary to render a tenant in default.