Yes, kind of.

I shorthand it verbally unless I'm giving a full date, but typed, it's almost always yyyy-MM-dd HH:mm:ss (whichever part of that is relevant).

I do this because I believe it's the most logical, it sorts properly without having to use a datetime library, and it can't be confused with another system (is 12-1-2026 in the future or the past? No way to know just by looking at it).

Just shortening it to MM-dd could cause confusion with anyone not in the US so I'll typically include the year as well (also useful if I wind up having to look at old notes or emails to not have to figure out the year I meant ... Which has happened more than once ...)