There is no getting around it, mudguards are what you need for your winter adventures or for commuting. As we know the British weather is unpredictable and mudguards are essential to remain as dry as possible for as long as possible, helping keep the chill off. Preventing the excess dirt and water spray, even when its not raining, means you arrive at your destination dirt free.
The 'man up' mentality of simply increasing layers is outweighed by the benefits offered by well fitting mudguards to cope with the unpredictable British weather.
For you - Mudguards will protect your clothing and shoes from the wet, dirt and grit which will eat away at the material fibres, potentially damaging clothing, overshoes and zips, making them not fit for purpose. Once your clothing becomes wet through you will no longer be able to retain any warmth and continuing your ride becomes very unpleasant and potentially unsafe.
For your bike - Mudguards offer protection for the bike frame and its components including the headset, seat post, brakes and handlebars, and moving parts such as chain set, rear and front derailleur. Keeping these parts protected helps prevent basic mechanical issues due to crud or rust, decreasing the wear and tear from the elements. However, even with mudguards, it is always a good idea to dry and lube a wet or dirty bike before storing, even for the night!
For others - Riding behind others on a group/club ride, with a training partner or in rush hour traffic with other cyclists can be very unpleasant. Nobody wants to be covered in mud splatter and dirt in eyes or on glasses can be a serious hazard. Preventing spray from your bike is reduced dramatically by fitting mudguards.
Over the years mudguards have been redesigned to fit the needs and wants of cyclists, their bikes and their rides. This has led to a wide selection of mudguards being made available: