I ride my 07 Bianchi Nirone most days of the year, I don’t see any point in modifying it for the winter as all it’s components are waterproof. Actually I lie, in the winter I tend to only need 1 bidon. never saw the point in mudguards, they just seem to collect sharp things and cause punctures in my experience (also they look lame). A little spray never hurt anyone.
The GF rides her Madone all year around as well and never had any problems with it being carbon.
Although I do use a Specialized Langster for my commute when I’m working in Hertfordshire (no need for gears as there are no real hills in Herts) and the only thing that has changed for the winter is tyres with more tread as half my commute is dirt track.
Tom KP