I am designing a survey that will have to be administered over the phone. While I have used 7-point Likerts on many occasions, saying "On a scale of one to seven" out loud makes it seem, suddenly, extremely unintuitive. If I were to ask a friend something, I would ask on a scale of 1 to 10.
I understand the issues behind having an even number of points, but is there any other strong reason not to ask 1:10? My own sense is that the simple familiarity of the scale would allow for more reliable answers, and I have no desire to list (each time) "Not at all, a little, somewhat ..." which I anticipate will simply exhaust my already time-strapped and generally no-nonsense population. 1:10 is fast, and low burden. Or will that familiarity itself result in biases?