This change occurred over several years, starting in the late 1990s and early 2000s.
Historically, many mattresses were designed with two sides, which allowed for flipping and rotating to extend their lifespan and reduce wear on specific areas. However, as mattress technology evolved and new materials were introduced, one-sided mattresses became more popular. These newer models often included specialized layers and comfort materials, making them more comfortable and supportive, while still maintaining a reasonable lifespan.
One of the main reasons for the shift to one-sided mattresses was cost-effectiveness for manufacturers. Producing one-sided mattresses is less expensive than two-sided ones, and the demand for more affordable products contributed to the change.
Nine Clouds Beds still sells two sided flippable mattresses, in fact every one sided mattress in our showroom can be made two sided for an extra charge (20-25%)