There is a myth being circulated by some marketers of tea that large leaf teas are always better than small leaf tea. This is not so.
The truth is that there are some teas, particularly those which are strong and aromatic, that are enjoyed better as a small leaf size (or to use the terminology of the tea trade, a broken grade).
This is particularly true of teas to which milk is generally added.
After tea is processed it is separated into leaf size by vibrating sieves, so larger leaf sizes and smaller leaf sizes are produced by the same process and at the same time.
What is true is that the larger leaf teas are more subtle, not stronger or better, than smaller leaf teas.
As a general rule the smaller the leaf size, the stronger and quicker the infusion.