Originally Posted by crt

I am making a block of the month sampler quilt. Some of the blocks have as few as maybe 15 pieces that we cut to make a 12" block. There is one that I'm making this month that has over 70 pieces that we cut to make a 12" block! On the block that has a fewer number of pieces, we use a regular 1/4" seam. On the blocks with a lot of pieces, we have to use a scant 1/4 seam, so basically about 1 thread less than a 1/4. If you take 1 thread bigger seams over 70 times, your block will never measure 12 inches, and that's a lot of work to have a block end up way too small.

If you're making a quilt that has blocks that are made up of roughly the same number of pieces, your consistent 1/4" seam will work fine; if not, you have to compensate for the space the thread and pressing takes up. I hope I'm explaining this so that it makes sense!