I've made a lot of bags recently for Christmas presents. First up is the Jane Market Bag:
For some reason when pulling/purchasing fabrics for these I was certain that I could make the exterior with fat quarters. You can't. I started cutting the first bag and realized I didn't have enough fabric. I altered the pattern on the first three bags and adjusted the size of the side pieces to make them fat quarter friendly since I didn't want to buy more fabric. It ended up working out just fine.