I agree with Sara. It's up to you. I adjust things all the time for custom orders. Like, changing a pocket size, or even adding a solid color instead of a print. These things (so long as I have the fabric on hand or would normally have it on hand) I do not charge for. If I have to redesign something (like a different strap or a different style pocket) or the request requires more or different fabric, then I charge a little extra.