The hairdressers at the place I take my 10 year old DS always seem to want numbers when they ask this question. My DS has a shaggy mop of wavy hair that sticks out in all sorts of absurd directions when badly cut which is most of the time and it doesn't end up the same length dry as it was when it was sprayed wet. I can't deal with whether it should be two inches or 5 cm or 27.27592 mm or whatever. I just want it (a) long enough to keep the wave and (b) short enough to be tidied up a bit. But when I say this they look at me with a bovine stare that tells me they really don't know what I mean. They're supposed to be the hairdressers. I don't do hair. Ever. I'm hopeless at it.
I suppose I am being unreasonable. This is what you get for keeping the price down to under £10 a cut. But would a slightly better service at a slightly worse price be too much to ask?