One of those sayings that is all too true is that one does not get a second chance at a first impression, do overs maybe, but not first impressions.

Pattern Editors may or may not be exposed to the photo of the project, but often their first impression is entirely based on the text.

A lot about the likely quality of the pattern instructions can be determined in Tools, Materials and Supplies listing. Just the presence or absence of it being followed by a “Stitches Used” listing.

it is my strongly held opinion that in today’s world those who do not list Metric are doing their potential customers a severe dis-service.

Any pattern author or even pattern user can easily see that “just letters” or just “numbers” don’t work if they actually look at:
https://wheatcarr.com/crochet/wheats-aluminum-crochet-hook-cross-reference.php
this chart is only a starting point, as due to some recent changes in sizing by several manufacturer it is in need of updating for purposes of “currently available”.

It is even more vital that metric sizing be included when referring to “thread” hooks since there are several standards (although I prefer the Japanese) Yet, even that can change of the years.

The meaning of D is not only subject to the Manufacturer whim, but even within the same manufacturer, may change suddenly. I have some BOYE size N that are 9.00mm and some that are 10.00mm –

I remember one particular author who had no idea (and we were unable to explain) how to use a caliper

In fact, a Pattern Author who wishes to “skimp” on the details, should, IMNHO, give metric diameter – since it is more universal and not subjectively based on the manufacturer other than for accuracy

Someday I need to finish this.