OOPS! Should Have Covered That in the Lease Date: 12/31/2014 A firm grasp of leases will benefit anyone who runs a company or has any interest in commercial real estate. Commercial leases are the single most important part of commercial real estate. They control the use and value of the property for both the tenant and the landlord. (Wonder if my children would call me Mr Landlord, no? but they live on my property)