Description
The YouTube API comes with limits for how much it can be used. Generally this application isn't much of a concern for hitting that limit unless there is a sudden influx of traffic which has only happened twice or extreme usage from user(s) which has also happened a few times. It is at least worth mentioning that the limit can be reached (see below).
This application is allotted 1,000,000 quota units which was the default at the time I made it. New projects are allotted only 10,000 quota units. In that regard this project is lucky, the average quota usage per day appears to be between 100,000 and 150,000 units which wouldn't work with the current quota limit and is why I share that key with my other project youtube-metadata.
Quota Reset
As reported in the Google Developers Console,
Daily quotas reset at midnight Pacific Time (PT).
If you get errors related to the quota being reached, waiting a day should solve your problems.