The answer to 'gutter guards sagging' is that gutter guards can sag for a few common reasons, including poor installation, heavy debris buildup, or the guards simply wearing out over time. This can cause the guards to pull away from the gutters, creating gaps that allow water and debris to get through.
The main symptoms of sagging gutter guards are visible gaps between the guards and the gutters, as well as the guards hanging down below the level of the gutters. This can lead to clogged and overflowing gutters, which can then cause water damage to your home's foundation and siding.