The commencement date is the date that a lease begins. In other words, the lease is commencing on this specific date. This is the day that the tenant takes possession of the rented property. Typically, a tenant's move-in date coincides with the commencement date. Some landlords may accommodate an earlier move-in date for special circumstances, and other landlords wish to adhere strictly to the lease. The commencement date is initially negotiated between the tenant and the landlord. External factors may impede a tenant's preferred commencement date such as if the property is not available or vacant at that time. For example, apartment communities usually require several days in between occupancies in order to clean and make the apartment move-in ready. Therefore, tenants shopping for apartment rentals may not have as much freedom in choosing the commencement date. Commercial building tenants may encounter the same obstacle for the same reasons.