The general rule of thumb is that gutter hangers should be installed every 24-36 inches. the variation of 24-36" is typically explained as being dependent on the severity of the weather in your geographic area,
We are based out of Central NJ, an area that doesn't get particularly harsh weather, however the consensus here seems to be that gutter hangers should be placed every 24".
It doesn't require that much additional labor, the expense is relatively minor and the last thing you would want is a callback from the customer, so spacing the gutter hangers every 24" is worth the peace of mind in knowing that the gutters have been installed as securely as humanely possible
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