I don’t have a link so I’ll try to explain how and why I trim after sewing the binding on. I start with binding that is 2.5 inches , then folded, square the quilt by marking with a pen instead of trimming, sew the binding on with a 1/4 inch seam. When I trim I leave 1/4 inch of batting and backing by putting the ruler at 1/2inch mark on the stitching line. The purpose is to get a full binding. I don’t know how that would happen if the quilt is trimmed before the binding is sewn on. I suppose it would work with a narrower binding but I like the 2.5 inch because I can use leftover binding cut into 2.5 inch squares for scrappy quilts.

Honestly I've only found it necessary when I'm working on a quilt with a scalloped binding. Otherwise I square up first, then apply binding. I've also found that if I do NOT press the binding in half lengthwise before sewing it on, it's always nice and full, regardless of whether it's a narrow 2" or 2 1/4" or a wide 3" binding.

Usually, I use the top layer as the binding. Fold it back 1 inch, and trim the batting and backing. So yeah, I trim before binding.

I'm a trim and sew. I don't need the extra under my binding as I apply it snug on the trimmed squared edge. When I put my binding on, I don't want extra steps. I also like my binding already folded and ironed. I cut my binding strip at 2.5" and then fold it and Iron it in half. Sew it on, flip and sew the other side! It is the last hurrah of finishing. I also do the same with a scalloped edge.

I sew binding on, then trim.

I trim first because I sew binding on the back first then machine the front

I am going to try this on my current quilt project. I usually trim first but this sounds interesting. Thanks for the instructions!

I don't mark as my-ty does but I do trim before sewing on binding as I usually have quite the excess of backing/batting after sandwiching. I place my ruler 1/4" from edge of quilt and trim batting to that size then sew on binding. I use a 2.25" binding. I also learned it's much easier to not iron the binding in half. Line up the cut edge of my folding binding to the edge of the quilt and sew onto the front of the quilt. I then hand stitch to the back.

I trim the back and batting down to about 1.5" before adding the binding. It reduces the bulk and gives the feed dogs material to grip when sewing the binding on. If the back and batting are cut right to the edge of the quilt there is no fabric on the right side to balance the pull of the feed dogs, at least on my machine. Trim to the edge after the binding is attached.

This is what I do as well.