That is too broad a question to answer in anything short of a book length. In the 550s Venice was a a collection of fishing villages. The capital of the Byzantine empire had a population of around 1 million and was one the richest cities on the planet. However by the 1430s Venice was the wealthy capital of a large maritime empire and had considerable territory on the Italian mainland. Byzantium was a shadow of its former self. The city walls now contained a series of villages with farmland in between with the prestige buildings dotted around.

The empire in the the 1000 years of the Medieval period underwent numerous social, administrative and religious changes. The empire had shrunk and expanded several times. An Anglo Saxon freeholder in the 650s had different quality of life to an Anglo Saxon serf in the 1120s. A citizen of an Italian republic had different variations in quality of life over the 1000 years.

You need to focus on a century and a region to get a compare and contrast.