Especially if I made or altered the pattern using EQ8 I test out my calculations with one block before I cut the rest of the my fabrics. Rather have one incorrect block than all of them. I remember before I even knew anything how to make a quilt back in the early 90's. I designed a quilt, cut all the pieces and then try to assemble them. Found out I didn't take into consideration the seam allowances, angles for triangles, etc. It was an utter mess. I threw it all away and didn't try to make another quilt.
Of course now things have changed, I've gotten a bit of education on how patterns are made and assembled. Have come a long ways since that 1st attempt....................and so glad I did.