Gutters have been used on buildings for hundreds of years. Many materials have been used to make the gutters to carry rainwater away from buildings — tile, stone, wood, metal of various types and the newest, vinyl. Leaves clogging gutters have been a problem as long as gutters have been in use.
Here are a few rules for installation that apply to all gutters. You need to have a gutter of sufficient size to carry the water load from your roof. I recommend buying the widest gutter (5-inch) if you have much rain in your area.
Gutters come in two basic shapes: box type and half round. The latter is not too popular these days. The gutter should also be placed with a pitch or drop of approximately 1/16-inch per foot. This gives a slope to the gutter so that the water flows along continuously.
Hangers should also be placed every 3 feet along the gutter. Some gutter materials can sag more than others, and it is important to give enough support so that this does not happen. There should be a downspout for every 30 feet of gutter.
It is also more important to eliminate clogging of downspouts than it is the gutter. Splashboards are another very important item that are often overlooked. Splashboards are placed at the bottom of each downspout elbow to carry water away from the foundation of a building. The most common styles are made of molded concrete.
There are many types of hangers, but they fall into two groups. There are hangers that fasten to the fascia board or the ends of rafters, and there are those that attach on the roof under the shingles.
I prefer the bridge type of hanger as opposed to the spike and ferrule. The spike and ferrule are a simple hanging device. The ferrule acts as a spacer for the trough; the spike goes through the front and back edges of the gutter and through the ferrule. The problem with this type of hanger is that the ferrule makes it hard to clean out the gutters when they become clogged with leaves and debris.
Leaf guards come in a variety of forms. One of the most important is a cage-type strainer that is placed in the opening of the downspout. Aluminum gutter screen is one of the simplest of leaf eliminators. Rigid grate material is also available that clips on to the outer lip of the gutter.
Hinged leaf guards are one of the newer innovations. The idea is to be able to swing them up and dump the leaves onto the ground. You mentioned that hinged guards are not recommended by installers; leaf guards depend on personal preference. It is what is most convenient and what works best for you.
Regardless of the type of leaf guard, they all need attention in areas where leaves are a problem. Even the guards can become clogged and cause water to flow across the clogged guard and down the side of a building.
Another new idea for gutters is a cleaner that attaches to a garden hose; it has a long handle, wheels and a high pressure nozzle. You move it along the bottom of the gutter from the ground and blow the leaves and debris along the trough toward the downspout.
All guttering requires periodic maintenance to make it work properly. I think you should be able to repair the gutters that you have and make them work for you until you may have to replace your roof. I hope this information helps.