Winter has been unusual and the roof and gutter system has taken a LOT of extra weight of snow and water, let alone tree debris like branches, leaves, seeds, fluff, and so on.
The system needs to be checked to make sure the gutters are still attached to the facia board. That extra weight through our snowy winter could easily have detached the gutter. If this happens, the gutter will develop a low area where water will pool. This will cause more droop of the gutter, and more water to collect. This is one way the gutter stops working properly.
The downspouts can get stopped up because of all our long winter. These need to be checked and if clogged, taken apart and cleaned out, then reassembled. A job a pro can do in a very short time.
Interesting process is going on with some gutters... actually most gutters are being chemical decomposition[washed away]. Our acidic rain passing through copper pipes in the gutter will take the lower aluminum pipe away with the water.
I have actually removed a gutter pipe that was only the paint cover of what used to be aluminum pipe. All the aluminum had been washed away leaving only the paint - looked like a downspout, but was just the paint!!
My point: Get your gutter system checked out by an experienced maintenance pro who has seen our houses change over the last 20 years.