It's interesting how much life really changes as we get older. When we're young -- say, in our late teens and early 20s -- we have ample time for ourselves, but not much money to make the most of that time. Once we hit our 30s -- the time when we typically settle down to start a family and are more established in our careers -- we find ourselves on more solid footing financially, but with much less time available than we had in our post-high school years. It isn't until the kids move out for college that we transition back to a life where we can focus more on ourselves and our interests, but by then, those interests tend to be radically different than the ones we enjoyed when we were younger. It's no surprise more and more couples are waiting longer to have kids -- or are opting not to have them at all.  Perfectly content with their sans-kids lifestyle, such couples are in no hurry to go from a life of unfettered freedom to baby bottles and Dora the Explorer. ...