The Massachusetts Department of Revenue requires the Assessor's Office to visit each property in town at least once every 10 years. These visits, called "cyclical inspections" are not coordinated with building permits. They are done neighborhood by neighborhood.
Town Inspectors, are currently doing these inspections. They have Town ID badges and their car license plates are registered with the Lexington police.
They will request to inspect the interior/exterior of your home, which is left to the residents' discretion. Door knocker appointment tags will be left at all residence where no one is home.
If you have any questions about this process, please call the Assessor's Office at 781698-4578.