床肉幾時換一次﹖

suggest 6 mth or a yr...cos the body weight can affect the tendency of the mattress...usually the "pat " area of the mattress will collapse faster

back pain is the major problem, also the back muscle cant have enough rest. U will feel more tired even sleep for longer time.

if u really dont want to buy a new one, try to turn over from left to right or top to bottom...save money ar ma