How big of an adjustment can be made when sizing a ring?
Typically you can feel comfortable in expecting that a ring can be adjust up or down two sizes without much trouble. Often larger adjustments can be made, but two size movements are common and trouble free. An exception to this would be some type of band where there were gems set side by side all the way around the ring. Another exception might be if the diamonds or other stones came far down the sides of the ring.