The style and level of protection worn by individual riders varies greatly and is affected by many factors including terrain, environment, weather, potential obstacles on the trail, experience, technical skill, fitness, perceived risk, desired style and others too numerous to mention. A cross country helmet and simple long fingered gloves are a good minimum for the majority of riding.
Limb protection becomes important when speeds rise, surfaces become loose and sketchy, terrain technical and crashes more common and more severe. Full face helmets and armored suits or jackets are more suited to gravity and air orientated disciplines which use jumps and drops, where their extra bulk and weight is outweighed by the bigger and more frequent crashes with worse consequences. Still, within XC community, the typical road racing attire is what most riders use. Whatever protection is used it should fit well, be comfortable (or it wont be worn) on the bike as well as in the shop and suited for the particular type of riding. Gloves can offer increased comfort while riding, by alleviating compression and friction, and protection in the event of strikes to the back or palm of the hand or when putting the hand out in a fall. Gloves also protect the hand, fingers, and knuckles from abrasion on rough surfaces such as concrete. Many different styles of gloves exist, with various fits, sizes, finger lengths, palm padding and armor options available. Armoring knuckles and the backs of hands with plastic panels is common in more extreme types of mountainbiking.