Rightly or wrongly, many people wait until the end of the year to give money to organizations they wish to support, and that's one reason why charities and religious organizations often make special appeals then. Perhaps they also hope people will be filled with the Christmas spirit toward the end of the year, and will be more generous then.
Whatever the reason, I urge you to give as generously as you can this time of year -- especially since many groups are facing deep economic hardship. God has blessed most of us far more than we realize, and one reason He has given us so much is so we can help those who are in need. During a time of great celebration and feasting, the people of the Old Testament still kept "giving presents of food to one another and gifts to the poor" (Esther 9:22). May this also be true of us.
But I also urge you to give prayerfully -- that is, seek God's will for your giving. God knows that you can't do everything or meet every need. But you can help some, as God directs you. If you aren't familiar with an organization ask your pastor about it, or check to see if it's a member of a recognized monitoring agency (like the Evangelical Council for Financial Accountability).
What we do with our money is important -- but even more important is what we do with our lives. Is Christ at the center of your life, and are you seeking to follow Him every day?