"Measure Twice - Cut Once"

I finished Mom's skirt yesterday. I love the serger for this kind of project. Fast & neat. Now, just let me tell you about the saying "measure twice and cut once". Mom wanted the hem at 27 1/2" so I cut the fabric at 27 1/2". I knew it was wrong as soon as the scissor cut into the first 1/4 ", but it was too late. I cut it off and made a 1/2" hem, so the skirt is hemmed at 27". I wanted to use a 1"hem. Sorry Mom :(