One day, many decades ago, in maybe 1980, I was walking down the street wearing a grey trilby.
A man stopped me and said 'Why did you buy a hat like that when instead you could have spent your money on drugs?'
Scale length = 2 times the distance from fingerboard side of nut (or centre of zero fret) to centre of twelfth fret.
Distance of bridge saddles from nut (or zero fret) will vary slightly from scale length (as given above) due to differential of intonation on each string.