4 years has been a standard in many European countries but why not take it further, in Spain after the first test at 4 years unless the vehicle is a wreck then it’s given a two year ticket and does so until the vehicle is 10 years then it’s tested every year. Some exceptions are vans which are tested after two years from new then two years again until the vehicle is 10 years. Following the 10 years at the discretion of the tester if a vehicle is in a poor state they can demand testing every six months, plus all vans and commercial vehicles are tested every six months.
