34 hours, from acquaintance to friendship
A study found that it takes about 34 hours of investment to shift from a superficial acquaintance to a true friendship. According to the study, a total of 11 interactions are required to move from acquaintance to friendship, with the average friendship taking 5.5 months to turn into something solid.
According to the study, "Lockdown made people rethink a lot of their friendships. And one of the big problems [has been] friendships are very dependent on continued investment of time, so if you aren't able to see individuals at the requisite rate, they're just going to slide."
The study found certain qualities are most important for friendship. In particular, 61% of respondents believe a sense of humor is an essential ingredient of friendship, and 44% say it's about holding similar values. For 26%, friendship is driven by similar interests and activities. People also say friendship is based on being trustworthy (26%) and reliable (23%).
The researcher Robin Dunbar became famous for his classic theory that people can maintain meaningful relationships with about 150 others. This is based on brain size, but it’s also based on the amount of time and investment it takes to maintain connections with each other. Within their 150 relationships, the average person has about five people who are close friends — the people you can really rely on, and with whom you have the deepest relationships.