it sort of depends on the bike for me, i have a fender bender and crud catcher on the front of the full susser with nothing out back.
i sort of enjoy getting covered in mud, its part of mtbing for me, but i need to be practical too, i wear contact lenses, therefore i need to protect my eyes from *debris*.
however, on the road bike i view them as pure luxury, and who doesnt enjoy a bit of luxury, now and then?
like a dropper post/30 speed/full suss/ti frame/fatbike/disc brake etc, yeah you can manage without them, but they make biking better.
(imo)
(delete as applicable)

To me a large portion if the fun comes from getting out, wet and muddy. I would hate riding in the mud if I didn’t at least get a bit covered in mud I would just feel like I had a slow slippery punishment.

never done guards, might do on my commuter but only because no showers at work

FWIW I’m used to riding in wet and cold for long periods without guards or any of your namby pamby waterproof nonsense, and love it…

Me in Snow by j.buckle, on Flickr

(But still re-visited this thread to look for commuter mudguard recommendations 🙂 )

I’m with the King of Coffee the one good thing about mud is getting covered in it like a small child! 😀

On my road bike I hate the spray and dampness up my back so go for guards.

MTB ones look rubbish and always twist around etc making for much faffage!

If you want to look like some kind of bed wetter then go mudguards, don’t see rugby players wearing easy wipe shirts and water proofs when it’s muddy

MTB, no guards.
Road/commuting in winter, SKS raceblades.

I use rear mudguard and front small guard, just too muddy round our way to ride all winter esp mostly in the evenings so even colder and strangley (or is it my imagination) wetter. Rear ones look and perform pretty badly esp with 150mm rear travel but it stops me getting it in the neck about muddy washing machine. 😀

commuter – yes
FS and road bike – no