There are a total of 257 collectibles (40 Artifacts, 71 Logs, 73 Weapon Parts, 61 Circuits, 12 Blueprints) in Dead Space 3. The video guide below will show you all their locations. Blueprints are needed to develop new weapons. Weapon parts and Circuits can be used to upgrade and customize existing weapons.
Your collectible progress will be saved each time you reach a new checkpoint. If you die or restart the last checkpoint you will have to collect some items again. You can keep track of your progress in the chapter select menu.