For a birthday present, I got myself a kit 3D printer - Prusa i3. Came as a full pile of parts that needed assembly. The online manual said I would need about 8hours, luckily I completed it in about 5. With quite a lot of head scratching, there were several key steps that needed re-working. Either because I put it together wrong (not looking at the pictures or words correctly) or more often, key points were actually missing - helpful.