Where RPZ rules apply, a landlord generally must show that a statutory exception applies, not simply that local rents have increased. This may include proving that the property was not let during the previous two years or that it has undergone a substantial change in its nature, depending on the circumstances. The landlord should provide the required notice, supporting evidence and, where applicable, comparable rents and notification to the RTB. If the tenant disputes the increase, the RTB’s dispute resolution process can decide whether the legal requirements were met.