Food related patterns would be pretty strong indicators for me as well, I think.
I only eat after 4pm (sometimes only from 6-10 or so) and people comment when I actually eat earlier than that, especially breakfast. I almost never use condiments or salt (I’m on a very low sodium diet and have been most of my life; I don’t use salt outside of baking, and that’s half salt). Give my dopple unsalted fries and you’ll know right away.
Drinks would work well for me as well - coffee made a very specific way, or room temp water, mostly (I actively dislike cold and hot water).
And this is why I’m sterile.
I don’t want to be here, and I sure as shit don’t want to do that to someone else.. plus I don’t want to take care of some miniature asshole version of myself; I’m bad enough to deal with.