Kerning

While embroidering a text piece, I realised that I wasn't sure whether to measure the spaces between the letters as being between the very edges of each letter, or ignoring the 'overhanging' bits. I was doing the former (I figured it was fine as long as I was consistent), then remembered that the latter was probably what 'kerning' was, and that I should probably look that up. The former option seems more consistent, while kerning looks more consistent. Consistency is important to me, so it's a dilemma.