Dressed to the Nines

If someone is described as being “dressed to the nines,” as being very well dressed and wearing your best clothes. But why "the nines?"

The idiom goes back to the 18th century when there were no off-the-shelf suits available. If you wanted a suit, you had it custom-made, especially for you. In those days, a suit included the waistcoat so it took nine yards of fabric to complete. back then being dressed to the nines basically meant you were wearing a suit.

Court suit and sword worn by Charles Dickens in 1870.
The design was strictly specified and the suit was made by Charles Smith and Sons.
This is the only known suit worn by Dickens to have survived.