As I indicated in an earlier post on growing old in the Middle Ages, medieval people tended to wear out, on average, earlier than we do. This should not be surprising, given that they lived what we would consider a rough life and did not have the modern medicine that easily remedies things that would have killed a medieval person. (Medieval medicine was just was not the same. So much for all-natural cures and the secret wisdom of the ancients.)
This did not of course mean that people keeled over in their 30s. Indeed, a man who survived childhood and the childhood illnesses that vaccinations have essentially eliminated could expect to make it at least into his 50s, short of death in battle or in a serious farm accident, and some lived substantially longer. Women could expect to live about the same length of time, short of death in childbirth.
Here I want to discuss a bit more how medieval old people lived--defining of course "old" as they did, not how we do (I consider people in their 60s to be young and fun!). Old people were a much smaller proportion of the medieval population than they are of the modern western population, however one may define "old," because fewer of them lived to what we'd now call a ripe old age.
There was no specific definition of when one became old. Different authors came up with different definitions. However, multiples of 7 appear very frequently. "Age of reason" began at around 7, the age at which medieval children started their career training. At 14 one was no longer a child but a youth and could get married. At 21 one might or might not pass out of "youth"; interestingly, this is the one big turning-point we have kept. At 35 one might become mature or middle-aged or even "old," depending on who you were talking to. Or one might remain a youth or young man up to 49. Everyone agreed, however, that someone past 70 was not just old but very old. (This was of course approximate, because medieval people didn't really keep track of birthdays.)
One of the more obvious differences between a young or middle-aged man and an old one was that old men grew out their beards. Youths prided themselves on clean-shaven, sweet faces, to the extent that modern people sometimes have trouble telling the difference between young men and women in medieval illustrations (the clothing is the giveaway). Active men didn't want a beard that would get in the way of a helmet (for a knight). Monks were shaved every Saturday whether they needed it or not, and peasants were probably the same.
But an old man in the high Middle Ages would be proud of growing out a long, white beard, which became a symbol of wisdom. Charlemagne and Arthur were always described in twelfth-century epics as having such a beard. Even in the image below, probably a tenth-century copy of an image created not long after Charlemagne's death, you can see Charlemagne on the left as having a solid beard and mustache, whereas his son on the right has at most a 5 o'clock shadow. (Also note the scribe below; see my previous post.)
Medieval old people were expected to pass their wisdom on to the younger generation, stepping back from active farming, for example, as the next generation were able to take up the task. The Amish still practice this today, where at a certain point the old generation move out of the main house to a small, adjacent house, leaving the main house and the responsibility for the farm to a son or daughter. Medieval peasants probably wouldn't have the choice to stop working altogether, and they probably wouldn't move out, but they would hand off the heavier chores.
One of the concerns then, of course, as it is now, is who would take care of old people. As now, one's children were the primary candidates. But taking care of the old was also considered a "good work." In part this was because being old and being poor often came together, and the Bible was very explicit about taking care of the poor. In the late Middle Ages someone wealthy might establish a "hospital" that took care of the indigent poor whether or not they were sick. Masters were expected to provide small amounts of money to help retired servants. Servants would be expected to take care of an old master. Guilds would take care of their members in their old age. Churches routinely took in old people, as monks or nuns if they were educated enough to take part in the liturgy, or at least as part of the cluster of official poor people whom they fed and clothed.
These days, for most people, a major part of one's total lifetime medical spending occurs in the last few years of life, as serious illness (heart attack, cancer, stroke, broken bones) are treated to give the person another six months or sometimes several years of life. All of these would have carried off medieval people quickly. There was no medieval equivalent of the fear about being kept alive by machines.