“The logic is that values change and the market changes, and it changes in different ways,” said Larry Clark, the director of strategic initiatives at the IAAO. “So we recommend an annual reappraisal, just to be sure you keep up with that.”

Buffalo’s schedule, Clark added, is “not typical.”

But many municipalities in New York also lag the four- or six-year schedule, said Buffalo Commissioner of Assessment and Taxation Jason Shell. In Erie and Niagara counties, just 10 of the region’s 43 tax districts have conducted reassessments in the past six years, according to state records.

The city conducted rotating neighborhood-based assessments until 2009, Shell added, as part of a program in which every parcel was evaluated at least once every six years. But the program was paused out of concern that regular assessments were both costly and unnecessary at a time when housing prices changed little from year to year.

While the city did respond to early signs of market growth by launching this assessment in 2015, Shell said, “standard” delays – many related to digitizing old permits and deeds – pushed the process past its original notification deadline of July 2016. As a result, homes were only reassessed if and when their owners made changes to their property.