The holidays are in full swing, at least according to the retailers filling our inboxes and mailboxes and news feeds. And it’s no wonder: some retailers make 25% to 40% of annual sales during the holidays, and 2010 holiday sales are expected to be up 2.3% to $447.1 billion this year. How do you keep up the energy for an eight-week holiday season? It’s all about timing. From when you send your offers to how many days between reminders to which offers work best at which times of the season… Here’s a suggestion on a holiday calendar with timely offers.