What age should building blocks start at?

Soft silicone, foam or fabric blocks (like B. toys One Two Squeeze or Fisher-Price Baby's First Blocks) are aimed at roughly 6 months and up because they're safe to mouth and easy to grip. Hardwood unit blocks and connector sets such as KEVA planks are generally rated 3-5+ since they require more developed motor control, and reviewers in r/ScienceBasedParenting note heavier wooden blocks demand greater fine-motor skill than snap-together bricks.