Typically, the best time is at least 12 to 18 months prior to your lease expiration date. However, it can be an even longer period, depending on your size, any existing renewal options in your current lease, your need to right-size your space, layout and departmental dependencies, and your desire or flexibility to relocate. Your tenant rep is most effective when there is sufficient time to conduct extensive market research, evaluate all viable alternatives, and create an environment that provides the most leverage with your current landlord and other viable space options.