A reasonable division between the two, commonly calls for the landlord to take responsibility for the common areas and the tenant to take responsibility for its lease space. Don't leave these things to chance. Another key issue is when and how to determine the renewal rental. Tenant wants an objective method, agreed upon before the tenant must commit to renew. In theory, the marketplace of other properties keeps the landlord honest.
More involved procedures can be appropriate, such as engaging appraisers or other valuation experts.
Most landlords' lease forms make the lease subordinate to the landlord's mortgage. This means that, even though the lease is subordinate to the mortgage, the buyer at foreclosure has to honor the lease and not disturb the tenant's possession or rights, if the tenant is not in default. If you encounter a stubborn mortgagee or landlord, at least know where you stand and consider some relief, like asking for time to relocate if the lease is terminated by foreclosure. If tenant is doing all the work, then something to protect landlord will be required. Assignment and Subletting.