Be sure to begin the process of identifying and evaluating sustainability issues that the tenant might seek to implement in connection with a lease renewal at least six months in advance of the lease expiration. The reason for this long time period is that in many markets it can take several months, or more, to complete construction of tenant improvements, especially if permits are involved. Often, efficiency measures can be integrated at a lower cost if done in conjunction with other tenant improvements. In addition, “green leasing” is still a fairly new concept to both landlords and tenants and there are few “standard” practices or lease forms that can be relied upon by the parties. Therefore, it is best to allow plenty of time to craft action plans and corresponding lease provisions that will allow the parties to work together to create alignment and develop a lease that best serves the parties’ interests.