Unless you want a break over the holidays, the market is still active in my experience. I took time off last Christmas with auctions ending right up to Xmas and then starting again the first of January. My sales were great for December and January - February took a dive though.
Many people have time off during the holidays so they're out to shop, and they may have received money as gifts, bonuses from work or just have extra they put away for Boxing Day sales.
You'll have to give a very generous delivery timeframe to avoid unrealistic expectations othere here mentioned - I do it in my auction, in the EOA email and in my shipping confirmation. Even then, you'll get a few people emailing for a status, but it helps.