Medieval doctors received varying levels of training, with university-trained physicians passing exams but being expensive, while barber-surgeons received no training and performed basic medical procedures. Renaissance doctors were similarly stratified, with licensed physicians attending university and belonging to medical organizations, while traditional remedies were still practiced by housewives. By the late 19th century, medical education became standardized in Britain, requiring university study and exams, gaining practical experience, and having access to new technologies like microscopes. By the 20th century, doctors underwent about 7 years of specialized training in hospitals and continued learning through their careers to apply new medical advances.