You can do hip carries as soon as your Baby has good head control and can grab his toes or ankles with his hands, generally around 3-4 months.
Grabbing his feet means that Baby can bend his legs and squat, his knees come further apart and his pelvis is mature enough to be worn on the hip (or the back).
Hip carries give him a 180° field of vision, he can observe actively what's around and satisfy his growing curiosity.
Baby's eyesight comes to maturity at this same period of time.