The consumer rights organization Deco Proteste advises that because the Tax Authority (AT) does not automatically update factors like a building's age (coefficient of age/vetustez) or location, many property owners are overpaying IMI property tax. Property owners can use an online simulation tool to check if a revaluation of their property would lower their tax liability, but they must be cautious, as a revaluation can also result in an increase. Requests for revaluation by the property owner can generally only be made every three years. To benefit from a potential tax reduction in 2027, the application for revaluation must be submitted to the Tax Authority by 31 December 2026.