By now, you should be able to read a ruler to the nearest 1/32nd of an inch and to the nearest millimeter (mm). Precision measurement in automotive applications and other engineering fields go far beyond what we can see. The difference between something working properly and being broken can be the thickness of a hair!
Tools such as a micrometer and vernier caliper are essential for ultra precision measurement.
Watch this video and then complete the Micrometers lab.