I have been very surprised by the number of people on this board who have trouble sleeping. I count my lucky stars that I'm not one of them. I sleep for seven hours at night and three hours in the afternoon...same time every day. I do not use an alarm nor do I need to.
That said, I am a very light sleeper and will awaken at the slightest noise. I once walked down from a third floor master bedroom to the basement laundry room...the tap was dripping and it was keeping me awake. I probably have supersensitive ears because my eyesight was damaged in a fall down a flight of outdoor wooden stairs when I was three.
Earplugs are my saviour. Stuff 'em in and the world turns off and so do I. I like the soft foam type. You kind of squish one end and, when it's in your ear, it expands and silence reigns. Being frugal by nature, I wear one pair a day (for both nap and sleep). Then they go into a zippered mesh bag which gets washed once a week with the sheets using laundry detergent and bleach...into the dryer and the batch for the next week is clean and disinfected.