Clothing:  è  To wear and to carry!    It really depends on the conditions, but there should always be sufficient clothing carried to cope with the worst possible conditions.   This may mean carrying items in the rucksack that do not "see the light of day" but better that than not have that item when you desperately need it!   Starting from the inside out, a good thermal tee-shirt - one that feels comfortable and does not itch.   Thermal longjohns for really cold conditions (if you don't like the thought of wearing longjohns you can always call them skipants!).   Two pairs of socks - thin pair on the inside and thick pair on the outside.   Good leather boots.   Gaiters (tied or strapped underneath).   A sweater or sweatshirt - nice and  long at the back .   A fleece or a bodywarmer.   A waterproof jacket, preferably a breathable fabric and with a hood that fits snugly around the head.   A woolly or fleece hat  which covers the ears as well as the head.   Gore-Tex or Pertex, fleece lined, mittens (much better than gloves), and carry a spare dry pair if you can afford it.   Waterproof, breathable, trousers.  Skiing goggles or, at the very least, sunglasses.   In full snow cover, on a sunny day, it is possible to cause physical damage to unprotected eyes.    You will also bless your goggles or sunglasses if you get caught in a hailstorm, or if the wind is gusting to 80 - 100 mph and blowing particles of ice into your face at the same speed!   I burst a small blood vessel in one eye last winter because I was too slow in putting on my goggles.   Before leaving home I always refer to a checklist of what I should carry - just to ensure that I do not leave without some vital piece of equipment. Avalanches:  è  (Yes they do happen in Scotland!)   If snow conditions are such that avalanches are possible it is often safer (and easier) walking along the ridges, rather than across the face of a hill,    However, if walking on any ridges with a drop on either side, remember that, in winter, large snow cornices can build up and care must be taken not to walk on the overhanging snow.    Emergencies:  è  I always hesitate to give blanket advice regarding accidents or incidents on the hills in winter.   No two incidents are the same and, as each will involve different circumstances, so each may have a different solution.   What every winter hillwalker should do is to practise digging a snowhole or a shelter before being involved in an emergency situation, in order to see, from practical experience, how even a small scrape in the snow can provide a noticeable degree of protection. Litter:   è  It comes in many shapes and forms, from empty cans and bottles to crisp bags, the remnants of half-eaten sandwiches and the remains of various fruits.   It is entirely unnecessary to leave anything on the hills.   Most people bring their lunch in a sandwich box or container of some sort and this can be used for taking back all the leftovers, including banana skins, orange peel and half-eaten sandwiches. Opinion:  è  I have often been asked which is best - summer or winter walking - and the answer is easy.   If you get  a calm sunny day in winter, with full, firm, snow cover, where the snow sparkles like diamonds and the air is so clear that you can see half way across Scotland, then it is absolutely magical!   But you don't get many days like that in a Scottish winter!   It is far more likely that the mist will be down, the wind howling and the underfoot conditions either sheet ice or deep, soft, porridgey snow.