Deep sleep or slow wave sleep is not only restorative but is key to memory consolidation. This is especially true among the 55 plus crowd. The 55 plus crowd generally experiences a bit less deep or slow wave sleep.
Try going to sleep with the sound of a waterfall in the background. This recommendation is evidence based. A paper was published in the Frontiers of Human Neurosciences about the benefits of acoustic stimulation.
Sleep Tip #126: Deepen deep or slow wave sleep by falling asleep to the sounds of a waterfall.