Why don they use replicators to do instant ship repair?
For minor repair, it might be feasible, but we rarely see any sort of repairs actually being done. When Geordi says “30 minutes at least, Captain”, they might be replicating various components and using a transporter-effected swap-out. Recall, however, that the transporters and replicators use a lot of power. The replicators go offline in Alert situations, for example. It would be foolish to rely on such a system to repair the ship in emergencies, but it is doubtless used at other time. For large scale repair, I think the TNG Tech Manual says it best: “… if you could make a starship at the touch of a button, you wouldn’t need to…” ….
