A suitably large sample size is needed, but after a certain amount of samples, any added one will not provide much more security about the statistic. I think usually to be considered empirically important you try to get 100-300 samples. The rule of thumb for accuracy of a given statistic is 1/n, where n is the amount of samples.

Aaah, that tracks. Thanks :)

Could you elaborate on what a barrister is? I was completely confused why someone who works with coffee is talking about courts. I assume it’s a legal profession?