Les Binet and Sarah Carter get a little bit angry about some of the nonsense they hear around them… like the question 'is it ownable?'

Here we go again, we thought. It has happened so many times before. A senior client eagerly anticipates the unveiling of a new campaign idea. The reveal and the slow smile. He really likes it. It will stand out brilliantly – generally and from his competitors. He agrees with us that this will be an intriguing and distinctive tone of voice.

He doesn't even mind that we are not showing the target audience in the ad. But then we show our endline, which sums up the campaign idea and would be used across all our communications. He seems to like that too… at first. Then the moment's pause. And the four-word question: 'But is it ownable?'

It's interesting how often this question crops up. And it's interesting, too, how little it is challenged and picked apart to understand what false thinking might lie behind it. So what does it mean for an endline (or any other brand property) to be 'ownable'?

Well, one way for a brand to 'own' an endline might be to include the brand name itself, perhaps in the form of a pun, a rhyme or some sort of play on words. There are some good examples of this – Castlemaine's 'Australians wouldn't give a XXXX for anything else' comes to mind. But they are rare, and seem to be getting rarer, perhaps because they usually don't translate well, and so can't easily be used in global campaigns.

Another way a brand might own the line would be to base it around a product benefit – Domestos's 'Kills all known germs. Dead' is an example. But in a world where functional advantages are quickly matched by the competition, brands rarely own these product benefits for long. In fact, any bleach could make the same claim as Domestos does.

And this takes us to the nub of how branding works. As Byron Sharp puts it, brands succeed not by being different, but by being distinctive. Brands need to have a distinctive style, tone of voice, and personality. They need to have their own way of saying what it is they do. And the end-line's job is to sum that up in a catchy, memorable way.

Think about some of those great endlines that everyone remembers. Nike's 'Just do it', Tesco's 'Every little helps', BT's 'It's good to talk' – there's nothing inherently ownable about these words or the sentiments behind them. In fact, you couldn't come up with a more ordinary bunch of words if you tried. But each of these lines reflects an attitude to the category in question that is clear, distinctive and memorable. And over time, they've become inextricably linked to the brands in question.

And that's the key point - ownership takes time. The clever marketing directors who bought those amazingly successful long-running campaign ideas and endlines weren't agonising over whether they were ownable. Instead, they rolled up their sleeves, got behind them and set about owning them.

And that requires hard work, consistency, and, yes, financial investment.

It's the same with our personal names. Anyone could be called Les Binet or Sarah Carter, but over time we invest our names with meaning, until we grow to own them.

So let's try to avoid ducking our responsibilities. When we're next presented with a new potential endline, the right question is not 'is it ownable?' but 'how can we own it?'