Now that the winter is firmly here I hope you have safely stored your sails away. You should leave them on the boat while it is ashore on the hard. If your sails are still in the sail locker - go to the boat over the weekend and remove them. Dampness, moisture etc. together with a drop in temperature to below freezing will definitely have an adverse effect on your sail cloth. It is essential that you remove your sails and bring them home to a dry warm environment.
Now I know it is a bit late to say unpack them from the sail bag and lay them out to clean and dry them, but if you can that is what to do. Failing that, just storing them in the house in a warm dry place will help. After all you do not want to experience a tear in you sail next Spring in the first blow of the season!
Always look after your sails - they are expensive to replace!