I was adamantly against trimming (because why can't things just come out right?) -- I thought it was such a waste of time -- until I did a quilt-along with Edyta Sitar. As many of you will know, she makes quilts with lots of small pieces. She trimmed every unit. I thought, if she can trim all of those, I can at least try it this time. It made such a difference in the ease, enjoyment and accuracy of my piecing that I kept it up, and no longer see it as a waste of time. What I do now is make my seam slightly more scant than I would if I were aiming for perfect size, and trim off any excess. When I used to aim for the correct size, they were often slightly under and wonky. It's such a pleasure to sew with units that are just right. But I can totally relate to the reluctance to trim, as that used to be me. I trim in small bunches.