I managed a tanning salon for about a year and half and always encouraged clients to do a little flip action once in a while. Especially if you're a newbie to the tanning world. As another gal said, many people will form white spots, or begin to notice the sides aren't as tanned as the rest of the bod. Of course there's the underarms as well...those bad boys need tanning too. Truth about it (if you are concerned with it) your booty gets the best coverage when you flip...the bulbs on the top of the beds are ALWAYS stronger. And more often than not, the bulbs on the top are the ones that get changed when s'pose to. It really all depends on the place. Some owners like to keep a little extra dough in their pockets and run the lamps 200-500 hours longer than suppose to. Saves them money and has you coming back in more often than needed because you're just not "satisfied". If you've been tanning your whole life and wonder why some places produce better tan...there's your reason. This may be one of those TMI comemnts...but i'm italian...we don't have those moments in life..heh. Ever seen a guy nekkid and his booty is tanned all with exception to the crack area (there's gotta be a better word for "crack")...anywho...men never flip...i think for more obvious reasons. But, the booty gets plastered onto the bottom acrylic and ends up with a white spot in that vicinity. For me, 70% of my tanning experiences are found falling asleep and being RUDELY awakened by the quick drift of cold air....the other times...i rotate. Enlighten yourself...go in and ask a few different places how often they change their bulbs...when the last time the bed you used had it's bulbs changed....some will answer...many stutter through their answer...and the rest...have absolutely no clue. Get the most for your money when tanning. (dayum, i talk too much)