Final answer:
A child's eyes should be consistently well-aligned by six months of age, which coincides with significant development in vision and motor skills.
Step-by-step explanation:
A child's eyes should be consistently well-aligned by approximately six months of age. Around this period, an infant's vision is almost as sharp as adult vision, enabling them to pick up objects, transfer them from hand to hand, and start to discriminate depth. This stage is also marked by infants pulling themselves into a sitting position and beginning to enjoy vocal play, indicating that their overall development, including visual alignment, is progressing well.