Currently, you can simply delete a video and re-upload a new one at no extra cost. The quota usage resets when media is deleted, allowing you to upload additional media.
Upcoming changes to Revisions:
We incur video transcoding/processing costs each time a video is uploaded. These costs are significant enough, especially to generate multiple versions (1080p, 720p, 540p) and are not included in the current pricing. Therefore, we cannot continue to offer free revisions in the future, and they will count against your upload quota usage.
Note: Failed uploads/transcodes won't affect your quota usage.