Common mistakes include relying on a verbal objection, failing to check whether the increase notice is written and properly served, and missing the RTB’s time limits for raising a dispute. Tenants should keep the notice, tenancy agreement, rent records and relevant messages, and check the current rent-setting rules on the RTB website. Do not simply stop paying rent; continue paying the undisputed amount while seeking advice. Whether an increase is valid depends on the tenancy’s facts and is ultimately determined through the RTB dispute resolution process or by a solicitor.