I think it's important to consider audience. If I'm working with the intent that what I write is legible to folks who only have a basic understanding of math, I'll usually use the multiplication symbol (NOT the letter x, but ×, intentionally in the middle). Someone with more advanced knowledge of math, who may be more inclined to think it's an x, because my handwriting is shit, I will typically use the dot operator. But then there's the whole other audience where I need to define what the dot operator does. At that point, I'm probably pulling up something like LaTeX, because, again, my handwriting sucks.

Funnily enough, when I write for the purpose of math, my numbers are more legible than when I just write down a number. For some reason, I code switch in my handwriting. Kinda obnoxious when I'm filling out forms.