Sustaining friendships -- and making new friends -- can be challenging, even when we know it's important. So how can we make our friendships last without feeling overwhelmed? And is there a formula to follow for making new ones? To find out, data journalist Mona Chalabi turns to her most trusted sources: data and her mum. Want to hear more from Mona? Check out her podcast Am I Normal? with Mona Chalabi, from the TED Audio Collective.

Mona Chalabi: What makes a friendship last? 

What makes a friendship last? 

50% of friendships are replaced every 7 years, yet overall friend count remains stable, highlighting the fluid nature of social bonds.

True friendships transcend time and distance, revealing who truly cares and remains a constant in one's life despite physical separation.

Maintaining friendships demands effort; you replace half your friends every 7 years, requiring 200 hours for a best friend.