In midlife, the competing claims of work and child rearing can force friendship onto the back burner. Then there's divorce, which divides spouses not only from each other but often from the friends they once held in common. When we retire, the migration to the Sunbelt takes a toll both on those who leave and those who remain behind. Though the number of friends may dwindle as we age, it seems our pleasure in them grows. And they steer away from those they don't care for.
Women tend to have more close friends than men do.
That's more difficult for men to do, because they tend to be very competitive. Women may need more friends, since they are more likely than men to be single in old age. That's partly because they have a longer life expectancy and tend to marry men older than themselves. Indeed, among people 85 and older, women outnumber men 5 to 2. Both men and women need friendship but approach it differently.