Always sharp pencils
It’s a small thing, but in my workshop and studio I use Paper Mate Sharpwriter mechanical pencils to mark and measure. They are cheap (35 cents), super lightweight, very finely precise, have a good eraser, and are forever sharp by simply rotating the end. They are cheap enough that I have them everywhere, and wouldn’t care if I lost one, but they are bright yellow and none of them have ever broken. I hear they are favored by students as well. — KK