If the word ends in silent e, drop the e and add the suffix, unless the final e is needed to preserve the sound of the preceding consonant.
Which spelling word requires the final e to preserve the sound of the consonant before it?
acceptance
alliance
attendance
condense
condolence
conference
defense
existence
expense
experience
grievance
immense
intelligence
intense
interference
nonsense
nonsense
occurrence
perseverance
remembrance
repentance
resemblance
resistance
superintendence
vengeance
vigilance