Unless your sailboat is a small daysailer you simply turn upside-down or cover, it will require winterizing in any climate where freezing temperatures may occur. You can pay the boatyard or save considerably by learning to do it yourself. Most important are draining and winterizing all water systems and the batteries and engine as well as protecting the whole boat from moisture that may freeze and expand to ruin fiberglass, wood, and other parts of the boat. Once you make a checklist appropriate for your own boat, it's not too difficult to do it yourself. You can also easily learn to shrinkwrap your own boat.