I save the ink or pencil lead to do so by not dotting my i's or j's.

I only put the "uptick" and "basebar" on my ones if they're going to be in the same context as a lowercase L, otherwise, my l and 1 are indistinguishable as straight lines.

I had a professor who would use a capital and lowercase V, the Greek nu (ν), and lowercase r, sometimes all in the same formula, and it was impossible to tell them apart with his handwriting. I had another professor whose handwriting was so consistent and legible that it may as well have been typewritten, if it weren't on a chalkboard.