29. Only watching what you eat before special occasions
Eating well shouldn't be something you only get into prior to major events or before/after holidays. Although it's normal to want to look your best on your wedding day or to slim down after you overindulge, watching what you eat and staying active should be things you're doing everyday and ideally for the rest of your life. Besides, why wouldn't you want to look fabulous at 30 and beyond?