Of course I don't live in a rainy part of the world. And when it does rain, I don't generally ride as a matter of practice.
They just add weight and clutter to a bike, in my opinion. But I have considered half and quarter fenders for style, or the small wide high set plastic fenders for muddy trails.
Depends on the fenders too. Big wraparound, like the Monarks, look the best. Big chrome wald fenders have a good look too. Skinny fenders don't get it for me.
I usually build what I call Dragsters, a subset of cruisers for sure with a fat back tire and a skinny front tire. This look almost always looks better with a back fender, but it needs to be a cool one like a peaked fender or a deep Monark style. I don't always use a front fender but here a rear fender wrapping around the front wheel looks good. I even mixed chrome and paint, the chrome on the front fender emphasized the chrome fork, while the painted rear matched the bike I call Wasteland.
I love my stock original Schwinn Collegiates with fenders. Middleweights too, especially with slimline tanks. But anything I've cobbled together lately has been klunker or strandie style with no fenders, so there's that. I guess like you said at the top, it depends on the build.
I know I said "neigh" above, but my next three bike projects will all have em. Coincidentally, all three are for somebody else. Maybe I can convince her to change her mind. That's how wives work, right?
Yeah, verily. Always fenders. They are a pain in the keister to fit, mount and get the right radius but it shows you care. They really tie the bike together so it looks finished. If it's raining, so what?
As a number of folks have expressed, it depends. I kept the rear fender on this Spaceliner because I felt obliged to save the cool rear rack and the rack mounts to the fender. I did bob the fender because the rear brace was mangled. Fenders definitely add weigh and rattling noises, but sometimes the coolness is worth it.
Fender shaping is an artist's task, IMO. I can bend up a strut so it does my bidding, which is the easy part any apprentice can do. I admire people with advanced skills. I thought an English Wheel was some kind of cheese until a few years ago.
I like fenders in Winter because we get the occasional drop of rain around here.