I've learned the hard way on ironing too...
Now, I buy a 1/4 yard more fabric than I actually need to adapt for shrinkage, crooked cuts by cutters, etc.
I went to Ben Franklins today and caught the woman shorting me on my fabric. Asked for a yard, and she was cutting 3/8 yard.
They don't have one of those nifty cutter things on their table. They measure out the fabric, then fold it and cut on the fold. Nothing wrong with that, but sheesh!....give me what I ask for and I'll pay for what I ask for. I ended up remeasuring ALL the fabric I was buying and found 3 other pieces that were short at least a 1/8 yard. Glad I checked!!