Plastic guards are relatively cheap and some contain a fire retardant - well worth it if you're in a fire-risk area. They are fast and easy to install. You simply bend the roll into a converse arch within the guttering.

The hedgehog is a bottlebrush-type guard. Leaves get caught in the bristles while rain easily passes through. The advantage of this style is that it can bend around corners and it can be cleaned by lifting and shaking.

Metal guards are designed to be installed permanently, but they can still allow access to downpipes. They come in different profiles, to suit different roofing materials. Unless you're a confident handyman who's comfortable working on a ladder, it's worth paying a professional for installation.