The asessor is obligated by New York State law to maintain assessments at a uniform percentage of market value each year. The assessor signs an oath to this effect when certifying the tentative assessment roll -- the document containing each property assessment. The physical description (or inventory) and value estimate of every parcel is required to be kept current. In order to maintain a uniform roll, each year your assessor will need to analyze all of the properties in the municipality to determine which assessments need to be changed.
The assessor also performs many other administrative functions, such as inspecting new construction and major improvements to existing structures. This ensures that the record of each property's physical inventory is current and that the appropriate improvements are assessed.
The assessor also approves and keeps track of property tax exemptions, of which the most common are, senior citizen, School Tax Relief (STAR), veterans, agricultural and business exemptions.