Tartan- which is your method for measuring? Tks
Most of the tutorials say to measure near the top, bottom, and then center and take the average of the 3.

If my quilt is measureing square to start with, I often just cut and sew and then trim the ends. If the quilt is not as square as I'd like, then I'll cut the borders the same and ease them in so that the sides are now the same length.

I will measure afterwards and rarely have any problems doing this, but I use to sew professionally, and when you sew 8 hours a day for several years, you get very good at knowing how to hold the fabric so it feeds correctly without pinning.

If I have a top that is divided into sections (like 12" blocks) I'll often lay the border on my mat and mark it every 12", but I am doing that more to make sure all the blocks stay 12" than to get the border correct.

I have always cut mine just a bit longer than the quilt top and just sew. I've been lucky that mostly they come out just fine.

You can use the borders to help square a quilt. The middle measurement is used a lot but you can do averages. The idea is that pin and help ease or stretch a bit (pieced fabric can grow) and with the borders the same on each side will even your quilt. The same for the top and bottom.

Sometimes with smaller quilts or ones that are more casual, you can just add a border strip, sew and cut off. However, on longer quilts, doing this can create an 1” or more difference per side.

This is about what I do. Use the border to measure with.

I never measure like the above. I measure through the center using the border to measure with. Cut both side borders this size. Then I measure the same way with the top and bottom border pieces. I lightly smooth border with my hand.

I don't typically measure if I'm using one fabric but I usually have a good idea of what the quilt was supposed to turn out to be and how much yardage I need. Whenever possible I prefer to cut along the length of the fabric for a solid piece, "measuring" it along the bed of the quilt and then adding a couple of inches, but sometimes I don't have enough length for that so I will piece it if needed, that's usually cross grain. I prefer to miter my corners if I can. When I use corner stones, I still only rough measure and then trim the extra length along the edge line of the quilt, so typically I'll put the top on first, cut to the edges. Then piece the cornerstones to the length, put that on the one side, trim off the bottom. Then it's the bottom corner stone to the bottom piece, trim to the edge again. Finally the last side, starting with the cornerstone again and trimming down (keeping the seam line in mind), and fitting in that last corner. Sounds more complicated than it is.

I do a lot of pinning, both with piecing my blocks and putting on my borders, about every 2", far enough down that the pins don't go to/under the foot but enough that it holds my pieces securely, I had more problems with wavy/extra/stretched fabrics when I tried to go pinless. Your mileage may vary but I believe a lot of my success is in a lot of pinning and a lot of pressing.

Jingle, I am pretty sure it was a post by you several years ago who inspired me to stop futzing around with a measuring tape and use the middle of the quilt itself. It works like a charm and saves time.

Thanks so much, everyone! :)