Ikea gets a 4-star rating, sometimes 4.5.
Words? Immediately dock 1 star.
If using a manifest ("part A, B, E used in this step"), which is necessary because not everything is as distinct as Lego bricks, and you don't provide a scale printout so I can sort the M6x10's from M6x12's, dock a point. Another point if you don't label the diagram with callouts and expect me to visually discern two similar parts by their 10pixel wide render.
Using fasteners of very similar geometry (see above) for no discernible reason, dock a point.
Low print quality of diagram with the toner chipping off? Insta fail.