One of the reasons I bought a new bike - a Boulder All Road rando - is just so I can always have fenders; my vintage Trek road bike (maximum tire width 25mm) has seriously limited fender options.

Also, while I like how good fenders keep you drier in the rain, what I really like is how they help keep the drivetrain cleaner; I don’t mind riding in rain, but I’m lazy and hate having to clean/relube chain/gears/sprockets to remove sand, grit and muck. Fenders make my bike maintenance much easier.

Finally, they’re useful even if you avoid the rain and ride after. Large puddles of water are nothin’.