I've usually used test strips, sometimes I've cut 8x10" paper into a couple of 5x7s and used what was left as test strips. Or I cut a whole piece into strips... if I can't tell from the test strip whether I'm 'there' or not, I've cut whatever size piece of paper I needed for the particular photo. (Or I just figure what the h... and go ahead and use a whole piece of paper and see what I've got.)
I don't know if I'd make smaller sized strips to be able to use less paper/save money, but I've cut smaller strips when I was running out of paper and didn't want to stop what I was working on! or had gone thru my last pack of paper faster than I thought.