Congratulations! After years of working and careful saving, you get to kick back and crack open that retirement nest egg. But don't get too giddy just yet. Retirees still need to avoid plenty of financial pitfalls as they transition into their golden years. And while you've certainly earned the right to spend your hard-earned money as you wish, some decisions will leave you in much better shape than others. Here are 18 choices, big and small, that you may want to avoid to stretch your savings.