This typically includes charges for taxes, maintenance, and insurance ("TMI"). This will also include items such as utilities, security, snow removal, grounds keeping, waste disposal, and other incidental costs. Tenants are asked to pay their proportional share of these items. Commercial leases may be gross leases, meaning that TMI is included in the minimum rent. They may also be net leases, which means that the property taxes are borne by the tenant. A double net lease means that the tenant is responsible for paying a proportionate share of property taxes and the building insurance. Finally, a triple net lease means that all three TMI costs, taxes, maintenance of the building and building insurance are payable by the tenant. These are usually calculated on a proportionate basis of the space rented and shared with other tenants, if possible. Exclusions on additional rent are negotiable. Examples of exclusions (non-exhaustive) are as follows: e.g. repairs or rent on areas of the building that are not accessible to the tenant; e.g. extraordinary usage (such as power use). Parties may attempt to negotiate a cap on the additional rent charged. Additional rent is typically estimated on a yearly basis by the landlord and billed monthly on top of the minimum rent charged. It may be prudent for parties to build in an adjustment mechanism if the estimated amounts are inaccurate. The tenant may negotiate a minimum notice period for an increase, and may try to align this with a minimum notice period for termination, to give the tenant an opportunity to exit the lease if the additional rent increases above an acceptable threshold.