A high-quality hotel with strong occupancy figures will most likely toss its mattresses every three to five years. For one lower down the ladder, with a management looking to squeeze every angle to save money, the answer might be closer to 10. There is really no way for the customer to tell the age of their mattress.
However, as it nears its double-digit birthday, even the best mattress will develop people pockets, those dips and bumps that might lead you to believe yours is not the first body that ever lay on this particular bed. Any decent hotel will invest in quality, innerspring mattresses, most likely from the hospitality range of a reputable manufacturer such as Sealy, Serta or Simmons.
That hotel will also have a maintenance policy that sees mattresses flipped, rotated and cleaned at least twice a year. If the mattress is ripped or soiled the hotel should chuck it straight away but some hotels will clean and hide the disfigurement. If you're a frequent traveller it's worth paying attention to the brand of mattress you're lying on in hotel rooms.
Chances are you'll sleep the sleep of angels on some, not so well on others – and that's a clue to what you should buy for the next home bed where you'll be spending a quarter of your life.