'I thought I was bad at keeping friends. Then I learnt the truth about the 5-year rule.'

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I used to carry a quiet, heavy guilt about the people I've lost. I'd scroll through old photos and feel like a failure for every unanswered text and every "we should grab drinks" that dissolved into years of silence. 

I looked at the gaps in my social circle and saw them as evidence of a character flaw — proof that I was too busy, too distant, or just bad at being a friend. I assumed that my evaporating list of contacts over the years was a sign of emotional laziness. 

But then I stumbled across the 5-year stranger theory, and it felt like someone finally gave me the permission I didn't know I needed to stop apologising for the natural passage of time.

Watch: Do you have 'Satellite Friends'? Post continues below.

The theory is as simple as it is jarring: in five years, the majority of people you interact with every single day will likely be strangers again. It's not a cynical outlook or a commentary on the fleeting nature of modern loyalty; it's a mathematical inevitability of the human experience. 

If you look back at your life five years ago, how many people from that specific part of your life are still in your daily rotation? For most of us, the answer is a small fraction. I've been fortunate to have a core group of friends that I've known for most of my life. Though even those friendships aren't immune from the ebbs and flows of life. There are periods where we're closer and periods where we've drifted. 

But the theory suggests that we are constantly rotating through ecosystems — workplaces, neighbourhoods, gyms, and hobby groups — and when we exit those ecosystems, we almost always leave the people within them behind.

Think about the colleague you share an office wall with, the one you go to lunch and share snacks with every afternoon. Or the barista who knows your oat-milk-latte order by heart and asks about your life. 

Think even of the friend you currently grab Sunday brunch with every single weekend. Five years from now, you might have changed jobs, moved to a different postcode, or simply evolved into a version of yourself that no longer fits into that specific social puzzle. 

When the common denominator — the shared office, the shared street, the shared phase of life — disappears, the connection usually follows suit.

Image: Getty

We've been conditioned to view forever as the only metric for a successful relationship. We treat friendship like a marriage that isn't allowed to end without a dramatic fallout or a formal breakup, when in reality, most friendships are designed to be seasonal. 

Some people are meant to be the main characters of your twenties, but only background extras in your thirties. By holding onto the idea that every connection must be permanent, we set ourselves up for a lifetime of perceived rejection and unnecessary grief. Accepting this theory means realising that a friendship isn't a failure just because it didn't last forty years. It was a success because it served its purpose while you were in that specific chapter.

This perspective shift has completely changed how I look at my social circle. Instead of mourning the people I no longer talk to, I've started appreciating the people I'm with right now, knowing our time together might not be forever.

There is something strangely beautiful about the transience of it all. It takes the pressure off the present. If the person I'm close with today is destined to be a stranger in five years, it makes our conversation right now feel more precious, not less. We don't have to be forever for this moment to matter.

And for those who last the test of time, well… It makes those connections all the more meaningful. 

I've finally stopped beating myself up over the ghosts of my past. I've realised that I'm not bad at keeping friends. I'm just participating in the standard cycle of human growth. 

We are all constantly rotating through each other's lives, offering support, laughter, or just a shared caffeine fix before moving on to the next station. Understanding the 5-year stranger theory hasn't made me feel more alone — it's made me feel more at peace. 

It turns out, you're not losing friends. You're just making room for the strangers you haven't met yet.

Listen: Em, Jessie and Holly discuss whether 'venting' has become toxic friendship behaviour on Mamamia Out Loud.

Feature Image: Supplied.