A baby fresh out of the womb loves the tight closeness, sounds, warmth, feel and movement of the sling and feels insecure and isolated in the western world's use of cribs, strollers, and mechanical swings that hold the baby apart. From day one to as long as you naturally and comfortably carry them. Certainly until 2 or 3 years of age. The diagonal sheeting across the back distributes the baby's weight throughout your torso, decreasing the chance of back strain and minimizing fatigue.
Most babies find it natural and comforting to be swaddled in the sling.
Parents in various cultures do strenuous work while carrying children this way . As you become accustomed to wearing your baby you will instinctively have a feel for how secure it is and will be able to carry your baby all day in a carefree manner. The weight of the baby causes them to tighten and lock. The nylon is not affected by the temperature of washing or machine drying.