Everyone dreads “scope creep.” That’s when a project keeps expanding, either due to endless revisions or the addition of new work that wasn’t part of the original plan. To avoid it, be up front with clients about the number of changes covered in the fees that you’ve agreed upon. Additional work and/or revisions can certainly be accommodated, but you’ll need to amend the original agreement so that you’re fairly compensated for it.
What qualifies as a revision? What’s the difference between minor changes and substantial ones? You’ll have to define the line between the two, and make it clear to your client before you begin work; add this definition into the Terms & Conditions section of your agreement.