I try not to have any to minimal variance. Once my blocks are done, I trim them all to the recommended pattern size, sure makes it a lot easier when piecing the top. Very little easing in when I do this important (to me) step. I have also been known to use featherweight interfacing on the back of my blocks too, helps to eliminate the give when piecing the top. I just have to much OCD in me. 🤪

I tell my students, "A good quilter is not necessarily a perfect seamstress, she learns how to compensate as she goes." I think we can compensate for up to 1/8" here and there.

As long as all my blocks are the same, I don't care if they are larger or smaller than the recommended size. But if I'm making a block for a swap, I will make one larger and cut it down to the accurate size, often floating the image in the center.

I'm pretty much zero tolerance, but I did notice when I was doing the final pressing on a top today that a couple of the HSTs were 1/8" off. No, I'm not going to try to fix them at this point. I want that quilt done!

Tolerance
 

As a LA that wiggle room counts. This is often what responsible for the little tucks on the quilt top. If one block is more relaxed than the next it moves. This is particularly important where pantos are being used as the operator is not necessarily looking at the quilt during the process. This also applies to mixing stable fabrics with stretchy ones.

This is a great discussion for me as I was just thinking about this two days ago as I was trimming a couple hundred HST's. The construction method, in my opinion left zero tolerance for variance in seams or cutting. It was 8 at a time HST's from an 8 3/4” block. I ended up having to pick out and re seam several that I could not quite get a 4” HST from and it involved moving my seam over Maybe 2x the thread width. Some came out pretty darn close and some I only had to trim a hair or small wedge on two sides of the HST. In hindsight, I think I’d rather cut the starting square even an 1/8” larger. I’d rather trim than fiddle with trying to take a slightly smaller seam allowance. I take so much time to cut and sew accurately, I feel I don’t get a fraction done that others seem to be able to whip up in no time. I have learned however, as other people have commented, it’s easier to get the quilt together if the units and blocks are put together as accurately as possible. I hate dealing with excess areas in a quilt I’m quilting and It annoys me if I cut off points or mismatch points or seams in the construction of my quilt. So that is kind of my “yard stick” for my level of accuracy. If I think I can get away with a little fudge factor, I roll with it, but I continue to strive for perfection, that will likely remain elusive! I do not strive to be a show quilter, so it’s all good https://cdn.quiltingboard.com/images/smilies/smile.png

I have also become aware of the fact some fabrics stretch more one way than another - so that if I decide to "press" a block like I'm rolling out pie crust, sometimes I do get more stretching in one direction than another.

Yes, I do know that I am supposed to "press" - but I have had good results doing the rolling out the pie crust method. But - I am super finicky about cutting everything on grain and having no bias edges (when possible) on the perimeter of a block.