What First registration date means for you
A car needs its first MOT three years after first registration (four in Northern Ireland), then every year, so this date sets the first test. It also shapes car tax: cars registered from 1 April 2017 pay the standard rate, and earlier cars use CO2 bands or flat rates.
When buying, check the date against the MOT history and the V5C. A private plate can make a car look older, never newer, so don't judge its age by the plate alone. Tax doesn't transfer to a new keeper: you must tax a car before driving it.