The half-fenders you see sometimes don’t work well since most of the business goes on at the ends. Fenders need to cover more of the tire than that.
Plastic vs. Metal FendersIn recent years, there’s been a growing fan-base for metal fenders and the folks that sell/like/endorse them go to great lengths to promise safety, but it's a case of confirmation bias. Metal fenders are (in the big picture) good, and look great, but they aren’t God, and they have their quirks that rule them out for us. Firstly, they're simply not tough or safe enough for even occasional offroad use and that's a kicker for us. They’re harder to mount, harder to modify, and can be noisy. They aren’t always, but often enough. The front metal fenders rarely (never?) have a quick-release device, and that can, in some cases, make them more dangerous. Sticks can crumple a front metal fender and send you flying over the handlebars and destroy your frame and fork. That's happened enough times to our nice bikes and nicer customers that we always recommend not using metal fenders, no matter how great they look. If you ride only stick-free roads and skinny tires with plenty of space between the tire and fender, okay, maybe.
In the end, we sell only SKS brand, German-made fenders. We’ve sold these for more than 15 years. Everybody here uses them. They’re as reliable as can be, and will work for you as well as they work for us. Easy on, modifiable (that means you can ream or drill a hole in one without a drill, if such a hole or two makes fitting it to your bike easier, or fitting them to a second bike, and now and then it does); and they’re a lot lot less than those fragile metal fenders. There’s a quick-release thing on the front fender, so if a stick gets jammed in there, all hell won’t break loose…just the fender, and you'll be okay thanking us for that quick-release.
Fender flaps extend fenders that need a little more length. The SKS Longboard fenders don’t, and they have built-in flaps anyway. The SKS Chromoplastics are great fenders, but are even greater with flaps attached. You can make your own, just as good as these but uglier, with duct tape.