This to the more accomplished writers:
If you are writing something — even just personal thoughts — that you know no one else but you will ever read, do you use your shorthand instead of your normal handwriting?
If not, why not?
Mostly I write in shorthand. Except book titles, for some reason I find it easier to write book titles, movie titles, names of magazines, in long hand.
Though I'm not one of the "more accomplished writers (yet)", I do. I've gotten into the habit of keeping a daily journal in Anniv GS, and writing up notes at work in the same. And I have no problem rereading what I wrote months earlier — except, on occasion, owing to my own GS handwriting problems (esp. where my proportions are off: Rs can look like Ls; Ks like Gs, etc., if one writes poorly; true of all GS systems by the way). GS carries very little ambiguity that context can't fill in.
I usually do a mix. When I'm flying along through vocabulary lists or grammar summaries for my language studies, I write shorthand to save time. I only really write longhand any more when I'm writing notes for other people, or if I'm writing on a bumpy bus/car ride which would make my shorthand a bit too sloppy for my tastes.
I write almost exclusively in shorthand, notes in meetings, interviews, my DayTimer, even grocery lists, except for something my husband needs to read. I have done this so many years that when I do have to write a social note, such as a Thank You or greeting card, I have to be very careful not to leave out letters or words. Crazy! But shorthand conventions rule my writing life!
Mix here — whatever comes to the brain first.
I write mostly in shorthand, except like you said, when other people need to read what I've written. The opposite applies too — since nobody else in my office reads shorthand, I write that if I don't want anyone casually reading it. I have a little steno that I keep all my notes from meetings and talking with people in it, mostly in shorthand.
Grocery lists for some reason are easier to deal with longhand though.