A few years ago, my guild did a block of the month and everyone who participated had to donate a 12 1/2" block for each block they made. I pieced 15 tops with 16 blocks per quilt -- and the first thing I discovered was that no one knows how to make a 12" block. We have some awesome quilters in our group and I love them all but I had to develop a bunch of coping tricks to make the blocks work together. I had ruffled blocks, blocks that were anywhere from 6.75 - 18" blocks, paper pieced blocks that came apart when I picked them up, and non-square blocks. It was a challenge to make the various blocks work, but in some ways it was fun -- and I learned a lot about coping with problem blocks.
It was a relief to hand off the tops to other folks who would do the quilting and binding. If I had made the tops myself and handed them off it may have gone faster but the quilts would not have been as interesting.