Sagging is a defect either due to the wrong composition of mattress especially of comfort layer, poor quality of fibres and foams of the comfort layer or broken spring.
A natural body impressions on the surface of your mattress happen no matter what. This is absolutely normal as long as it is between the advised indentation depths up to 5 cm (2 inches) during first 5 years of purchase. The indentations can either be a result of a normal compression of the top comfort layer due to your body weight in the same area of the mattress you sleep on every night to conform to your body or when you employ an inappropriate or inadequate base. The impressions can gradually come into existence or may happen within 2 months of your new purchase.
If you use a King size (150 cm) mattress, then the indentations is highly noticeable either in the middle or the outer sides depending on where the couple sleeps on every night. If the couple sleeps in the middle then the indentation will be in the middle and the mattress will develop a hump on the either sides, whereas if the couple leaves the middle space unoccupied then the mattress will develop a hump in the middle with the indentations on the outer side. In such a circumstances, a normal indentation can be mistaken as sagging of the mattress.
The magnitude of indentations can be minimised by taking a few simple steps as below:
- ROTATE/TURN your mattress every 2 weeks for the first 3 months after your new purchase, then once every month. If yours is a non-turn mattress then you need to rotate it only.
- SWITCH the sleeping sides to redistribute your weight to even out the effect of indentations. If you sleep alone, then keep switching the sides regularly.