Winter retreats often involve time spent inside and out, whether you're shopping, skiing or relaxing by the fire. Dressing in layers is the key to comfort. When you make your list, start with everyday necessities like underwear and socks. Plan to bring one extra pair of each in case they get wet or dirty. If you're going to play in the snow, add one to two pairs of wool socks to keep your feet warm. Next item on the list is thermal underwear. Then enough pants and long-sleeve shirts to keep you covered during your retreat. Add a fleece vest, weather-proof winter coat, snow pants, hat, scarf, gloves and winter boots and your list is nearly done. Include a swimming suit and flip-flops if there's an indoor pool or hot tub to soak in and a pair of warm pajamas. Shoes should be limited to all-purpose for indoor activity and shopping or browsing around town, boots and closed-toe dress shoes for when you go out at night. List your normal toiletries, but if you plan to spend time outside, include sunscreen and lip balm.
Kids need just about everything adults do but more of it. Again, start with the daily necessities like underwear and socks. Add three extra pairs of each to the list in case they get wet or soiled. For children who will play in the snow, put two pairs of wool socks on the list and two pairs of thermal underwear. Plan for each child to wear a clean outfit each day, and then add two more outfits. Include a fleece vest or pull-over, weather-proof winter coat and snow pants, hat, scarf, gloves and winter boots. Add a swimming suit and flip-flops if the kids plan to swim and a warm pair of pajamas. Children don't need a large variety of shoes, so keep the list simple with a pair of tennis shoes or all-purpose shoes and a pair of dress-up shoes if needed. List their normal toiletry items and sunscreen and lip balm if they plan to play outside. If you're traveling with a baby, include a stroller, baby carrier, bottles, formula, pacifiers, a few general toys, bibs, burp cloths, baby food and utensils, diapers and wet wipes.
If you're driving and have your own gear, put it on the list. Depending on where you're going and what activities are available, include skis, snow shoes, sled, snow board and ice skates on the list. Obviously, only pack the ones you need or plan to use. Add a fanny pack or day pack to the list, along with ski poles, goggles and ski boots/bindings. If you're flying and still want to use your own gear, put it on the list and ship it ahead of you. You can likely rent equipment once you reach your destination instead of packing it.