The same could be said about the post-referendum debate. The phrase "Brexit means Brexit" has seen the government through the summer, but has now reached the end of its usefulness.
It was designed to persuade doubting Remainers that the UK really will leave the EU, something Theresa May was once again forced to confirm during her news conference with President Obama here in China.
But over the months the slogan has inverted into something different, a symbol of the government's uncertainty about what Brexit will actually mean for our relationship with the EU.